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.

Infection and Colonization of Several Bermudagrasses by Ophiosphaerella korrae.

Bermudagrass (Cynodon spp.) is the most commonly used turfgrass in the southern United States where it is severely affected by spring dead spot (SDS) caused by Ophiosphaerella herpotricha, O. korrae, and O. narmari. In this study, infection of bermudagrass roots and stolons by O. korrae was characterized using a transformant that expressed the red fluorescent protein tdTomato. Roots of interspecific hybrid cultivars Midlawn and Tifway 419, C. transvaalensis accessions Uganda and 3200, and C. dactylon cultivar U3 were inoculated and observed from 2 to 14 days postinoculation (DPI) while stolons were observed from 2 to 22 DPI. For all five cultivars tested, a similar level of root colonization was observed; however, differences were observed in the rate of necrosis development. Necrosis of Tifway 419 and Midlawn tissues was evident at 2 DPI, in Uganda and 3200 at 8 DPI, and in U3 necrosis was often absent as late as 14 DPI. The fungus rapidly penetrated the root epidermis and colonized the cortex of all cultivars by 4 DPI. Colonization of stele tissues by O. korrae was rare in hybrid cultivars but common in C. transvaalensis and C. dactylon accessions. On intact stolons, the fungus did not penetrate the epidermis 22 DPI though epidermal necrosis was evident on the surface of only the hybrid bermudagrasses. Wounded stolons became necrotic in all cultivars. Infection and colonization of various bermudagrasses by O. korrae was found to be similar to that by O. herpotricha, suggesting that host genetic resistance may be used for effective management of SDS caused by both species.

Growth and development in rats given recombinant human epidermal growth factor(1-48) as neonates.

To assess effects of supraphysiologic doses of human recombinant epidermal growth factor(1-48) (rhEGF(1-48)) on neonatal rats, 10 litters of Wistar rats/treatment group were given 0 (formulated vehicle), 10, 100, or 1000 microg/kg daily by subcutaneous injection on postnatal days (PND) 1 through 6. Clinical signs, body weight, acquisition of developmental landmarks and reflexes, and behavior were monitored during treatment and for 5 weeks thereafter (to PND 42). A subset of animals was euthanized weekly from PND 7-28 and necropsied. Selected tissues were examined microscopically. Body weight gain at 1000 microg/kg during treatment was significantly less than control. Precocious incisor eruption, eye opening, vaginal opening, and preputial separation occurred at 100 and/or 1000 microg/kg. Acquisition of reflexes (negative geotaxis, wire maneuver, acoustic startle reflex, and visual placing) was delayed at 1000 microg/kg. Acquisition of adult locomotion was also delayed at 1000 microg/kg. These effects were transient, as locomotor activity at PND 28 and 42 did not differ from control. Effects on acoustic-startle responding persisted in females to final assessment on PND 42. Habituation to repeated acoustic stimuli was impaired, as well as response inhibition following a prepulse acoustic stimulus. rhEGF(1-48) induced structural changes in the skin, retina, kidney, oral and nasal mucosa, lung, and liver. Many of these changes were consistent with the expected mitogenic activity of rhEGF(1-48) and were transient in nature, as severity and incidence diminished with time. An exception was changes observed in the retina at 1000 microg/kg (rosettes/folds and focal defects in the outer nuclear/photoreceptor layers) that were still present 3 weeks after termination of treatment. Acceleration of developmental landmarks; suppression of reflexes, behavior, and somatic growth; and mitogenic responses in epidermal tissues have been reported in rodents treated with epidermal growth factor (EGF) derived from various mammalian species. These results demonstrate that a 48-amino acid fragment of human EGF produced by recombinant technology also induces such effects.

Preclinical toxicology studies with the angiotensin-converting enzyme inhibitor quinapril hydrochloride (Accupril).

Acute, subacute, and chronic toxicity studies, carcinogenicity bioassays, and reproductive and genetic toxicology studies were performed with quinapril, an ACE inhibitor used in the treatment of hypertension. Acute toxicity is minimal in rodents, and repeated dosing elicits gastric irritation, juxtaglomerular apparatus (JGA) hypertrophy and hyperplasia and tubular degenerative changes in the kidney, and reduced red cell parameters and heart weights in rodents and/or dogs. Other manifestations of toxicity, including hepatic lesions in dogs, reduced offspring weights in rats, marked sensitivity of the rabbit, and clastogenic effects at cytotoxic doses in the in vitro V79 chromosome aberration assay, have been reported with other drugs of this class.

Validation of automated behavioral test systems.

A positive control study was conducted as part of the ongoing validation program for developmental neurotoxicity testing in our laboratory using a standard battery of automated systems, consisting of rotorod, motor activity, acoustic startle, and two-way active avoidance. Female Sprague-Dawley rats were given 10 mg/kg diazepam (DZ) by SC injection or 20 mg/kg methimazole (MET) by gavage from gestation day 15 (DZ) or 17 (MET) through postpartum day 10; a group of control animals remained untreated. Offspring were assessed for growth, survival, developmental landmarks, and behavior. Although this study was considered useful for obtaining historical data, it offered few advantages in terms of validation of automated behavior test systems. Perinatal treatment with DZ resulted in no maternal toxicity and no adverse effects on growth or development of F1 offspring; a deficit in acoustic startle responding was the only behavioral effect observed. Treatment with MET resulted in maternal toxicity, reduced neonatal body weights, and developmental delays. Behavioral effects included impaired rotorod performance and acoustic startle responding (neonates), and enhanced motor activity and acoustic startle responding (young adults). However, effects on shuttle avoidance were not observed for either drug, and only one direction of behavioral effect occurred for the rotorod and motor activity systems. These results, as well as those from subsequent studies in our laboratory, suggest that it may be preferable to validate automated behavior systems using short-term studies in which young adult animals are treated directly with positive control agents.

Multiple genes, tissue specificity, and expression-dependent modulationcontribute to the functional diversity of potassium channels in Arabidopsis thaliana.

K+ channels play diverse roles in mediating K+ transport and in modulating the membrane potential in higher plant cells during growth and development. Some of the diversity in K+ channel functions may arise from the regulated expression of multiple genes encoding different K+ channel polypeptides. Here we report the isolation of a novel Arabidopsis thaliana cDNA (AKT2) that is highly homologous to the two previously identified K+ channel genes, KAT1 and AKT1. This cDNA mapped to the center of chromosome 4 by restriction fragment length polymorphism analysis and was highly expressed in leaves, whereas AKT1 was mainly expressed in roots. In addition, we show that diversity in K+ channel function may be attributable to differences in expression levels. Increasing KAT1 expression in Xenopus oocytes by polyadenylation of the KAT1 mRNA increased the current amplitude and led to higher levels of KAT1 protein, as assayed in western blots. The increase in KAT1 expression in oocytes produced shifts in the threshold potential for activation to more positive membrane potentials and decreased half-activation times. These results suggest that different levels of expression and tissue-specific expression of different K+ channel isoforms can contribute to the functional diversity of plant K+ channels. The identification of a highly expressed, leaf-specific K+ channel homolog in plants should allow further molecular characterization of K+ channel functions for physiological K+ transport processes in leaves.

Use of Saccharomyces cerevisiae for patch-clamp analysis of heterologous membrane proteins: characterization of Kat1, an inward-rectifying K+ channel from Arabidopsis thaliana, and comparison with endogeneous yeast channels and carriers.

Transport-deficient strains of the yeast Saccharomyces cerevisiae have recently proven useful for cloning, by functional complementation, of cDNAs encoding heterologous membrane transporters: specifically, H(+)-amino acid symporters and K+ channels from the higher plant Arabidopsis thaliana. The present study uses whole-cell patch-clamp experiments to show that yeast strains which grow poorly on submillimolar K+ due to the deletion of two K(+)-transporter genes (TRK1 and TRK2) are in fact missing a prominent K+ inward current present in wild-type cells. Rescue of such strains for growth on low K+ by transformation with a gene (KAT1) encoding an inward-rectifying K+ channel from Arabidopsis is accompanied by the appearance of an inward current whose characteristics are in qualitative agreement with previous studies in the Xenopus oocyte system, but differ in quantitative details. The ability to make such measurements directly on Saccharomyces should facilitate structure-function studies of any electrogenic or electrophoretic ion transporters which can be expressed in the plasma membrane (or tonoplast) of that organism.

Double-blind comparison of amlodipine and nifedipine retard in the treatment of mild to moderate hypertension.

The efficacy and safety profiles of amlodipine (5-10 mg once daily) and nifedipine retard (20-40 mg twice daily) were compared in 111 hypertensive patients (sitting DBP in 95-115 mmHg) during eight weeks of treatment in a randomised double-blind parallel group study. BP was measured 22-24 hours after the daily dose of amlodipine and 10-12 hours after a dose of nifedipine retard. Baseline sitting BPs of 175/105 mmHg and 168/104 mmHg were significantly reduced (P < 0.05) to 157/93 mmHg and 151/92 mmHg at the end of treatment in response to mean daily doses of amlodipine 7.3 mg and nifedipine retard 58.9 mg. There were no clinically significant changes in heart rate with either treatment. Three patients in the amlodipine group and five patients in the nifedipine retard group could not be considered in analysis. The total numbers of adverse events (considered related or possibly related to treatment) (42 vs. 36) as well as the numbers of patients experiencing such events (22 vs. 22) were similar in the amlodipine and nifedipine retard treated groups, respectively, but with a greater incidence of headaches in response to nifedipine retard and of oedema in response to amlodipine. Five patients in each treatment group discontinued therapy due to such events. Overall the results showed once daily amlodipine as equivalent to twice daily nifedipine retard in the management of mild to moderate hypertension.

Effect of S-methyl cysteine sulphoxide and its metabolite methyl methane thiosulphinate, both occurring naturally in Brassica vegetables, on mouse genotoxicity.

S-methyl cysteine sulphoxide (SMCSO) and its metabolite methyl methane thiosulphinate (MMTSO), both naturally occurring compounds present in Brassica vegetables, were investigated for their putative ability to inhibit benzo[a]pyrene (B[a]P)-induced genotoxicity in ICR mice. The mouse bone marrow micronucleus assay was used as an indicator of in vivo genotoxicity. Doses of 0.5 mmol SMCSO and 0.05mmol MMTSO per kg body weight significantly inhibited the formation of B[a]P-induced micronucleated polychromatic erythrocytes (MPCEs) by 31 and 33%, respectively, compared with control mice. Two higher doses of MMTSO (0.5 and 1.0 mmol/kg body weight) administered to mice displayed severe acute toxicity. The inhibition of experimental genotoxicity by these two organosulphur compounds present in Brassica may, in part, be responsible for the anticarcinogenic effect of these vegetables.

Expression of an inward-rectifying potassium channel by the Arabidopsis KAT1 cDNA.

Inward-rectifying potassium channels located in the plasma membrane of higher plant and animal cells contribute to cellular homeostasis and excitability. The genes encoding this specific class of K+ channels have not been functionally identified. This report shows that a single messenger RNA transcript from the Arabidopsis thaliana KAT1 complementary DNA confers the functional expression of a hyperpolarization-activated K+ channel in Xenopus oocytes. The channels encoded by KAT1 are highly selective for K+ over other monovalent cations, are blocked by tetraethylammonium and barium, and have a single channel conductance of 28 +/- 7 picosiemens with 118 millimolar K+ in the bathing solution. These functional characteristics, typical of inward-rectifying K+ channels in eukaryotic cells, demonstrate that KAT1 encodes an inward-rectifying K+ channel.

Development and comparative evaluation of a multiple-antigen RAST as a screening test for inhalant allergy.

We have developed a modified in vitro test for IgE antibodies, the multi-RAST, to detect antibodies of different allergen specificities simultaneously in a single tube. The multi-RAST is as sensitive for detecting low concentrations of individual IgE antibodies as the discrete RAST. We also evaluated the multi-RAST as a screening test for respiratory allergy to inhalant allergens in children by comparing the results of the multi-RAST performed by use of a mixture of SRP, TGP, and DF allergen-immunosorbents with the results of skin tests, discrete RAST tests for the same allergens, serum total IgE concentrations, and nasal smears for eosinophils in 100 children referred for allergic-disease evaluation. The results of the multi-RAST were more sensitive, specific, and efficient than the results of tests for serum IgE concentration and nasal eosinophils in establishing the diagnosis of inhalant allergy; the multi-RAST was the only diagnostic test that yielded results that were significantly associated with the clinician's impression of allergy. We conclude that the multi-RAST is a useful and cost-effective screening test for inhalant allergy in children.

Conversion of Elymoclavine to Paspalic Acid by a Particulate Fraction from an Ergotamine-Producing Strain of Claviceps sp.

The particulate fraction from the ergotamine-producing strain CLAVICEPS sp. PCCE1 catalyzed the conversion of [ (14)C]elymoclavine to paspalic acid. NADPH was required. Maximum conversion was 95%. Carbon monoxide (CO:0 (2), 4:1) and SK&F 525A (1.0 mM), cytochrome P-450 inhibitors, inhibited the conversion 94% and 50%, respectively. Minor amounts of paspalic acid (0.1 mg/1) were present in cultures. The particulate fraction from CLAVICEPS sp. SD 58, which accumulates elymoclavine in cultures, lacked activity for the conversion of elymoclavine to paspalic acid.

Attachment of community nurses to general practices. A follow-up study.

A follow-up survey has shown that in a two-year period the number of community nurses working in general practice attachment schemes rose from 11 to 24% (32% in counties, 13% in county boroughs, and 12% in London boroughs). The proportion of health visitors and home nurses rose from 15 to 29% and from 9 to 25% respectively. Reasons given for the 23 attachment schemes which were discontinued included administrative and personality problems. Careful preparation and continuing support, for both the general practitioners and the community nurses, are stressed for the success of these schemes.