Gammaproteobacteria as a possible source of eicosapentaenoic acid in anoxic intertidal sediments.

Eicosapentaenoic acid (EPA; n-20:5omega3) was found to be a constituent of phospholipids in three mesophilic strains of Gammaproteobacteria, which were isolated from anoxic most probable number series prepared with sediments from an intertidal flat of the German North Sea coast. Their partial 16S rRNA gene sequences identified the isolates as close relatives of Shewanella colwelliana, Vibrio splendidus, and Photobacterium lipolyticum. So far, eicosapentaenoic acid has mainly been reported to occur in eukaryotes and some piezophilic or psychrophilic bacteria. With decreasing temperature, relative contents of EPA (up to 14% of total fatty acids) increased in all strains. Additionally, Shewanella and Vibrio spp. showed a significant increase in monounsaturated fatty acids with lower growth temperature. Analysis of the phospholipid compositions revealed that EPA was present in all three major phospholipid types, namely, phosphatidyl glycerol (PG), cardiolipin and phosphatidyl ethanolamine (PE). However, EPA was enriched in PG and cardiolipin relative to PE. In the tidal flat sediments from which the isolates were obtained, substantial amounts of EPA-containing PG were detected, whereas other typical microeukaryotic phospholipids-being also a possible source of EPA-were abundant at the sediment surface but were present in clearly lower amounts in the anoxic layers beneath 5 cm depth. Therefore, the EPA-containing PG species in the deeper layers in these sediments may indicate the presence of Gammaproteobacteria closely related to the isolates. These bacteria appear to be an important source of EPA in buried, anoxic sediments beneath the layers harboring significant populations of benthic eukaryotes.

Spore dipicolinic acid contents used for estimating the number of endospores in sediments.

Endospores are heat-resistant bacterial resting stages that can remain viable for long periods of time and may thus accumulate in sediments as a function of sediment age. The number of spores in sediments has only rarely been quantified, because of methodological problems, and consequently little is known about the quantitative contribution of endospores to the total number of prokaryotic cells. We here report on a protocol to determine the number of endospores in sediments and cultures. The method is based on the fluorimetric determination of dipicolinic acid (DPA), a spore core-specific compound, after reaction with terbium chloride. The concentration of DPA in natural samples is converted into endospore numbers using endospore-forming pure cultures as standards. Quenching of the fluorescence by sediment constituents and background fluorescence due to humic substances hampered direct determination of DPA in sediments. To overcome those interferences, DPA was extracted using ethyl acetate prior to fluorimetric measurements of DPA concentrations. The first results indicated that endospore numbers obtained with this method are orders of magnitude higher than numbers obtained by cultivation after pasteurization. In one of the explored sediment cores, endospores accounted for 3% of all stainable prokaryotic cells.

Distribution of candidate division JS1 and other Bacteria in tidal sediments of the German Wadden Sea using targeted 16S rRNA gene PCR-DGGE.

The bacterial candidate division JS1 dominates a number of 16S rRNA gene libraries from deep subseafloor sediments, yet its distribution in shallow, subsurface sediments has still to be fully documented. Sediment cores (down to 5.5 m) from Wadden Sea tidal flats (Neuharlingersieler Nacken and Gröninger Plate) were screened for JS1 16S rRNA genes using targeted PCR-denaturing gradient gel electrophoresis (DGGE), which also detects some other important Bacteria. Bacterial subpopulations at both sites were dominated by Gammaproteobacteria in the upper sediment layers (down to 2 m) and in deeper layers by members of the Chloroflexi. The deeper layers of Neuharlingersieler Nacken consisted of grey mud with low sulphate (0.1-10 mM), elevated total organic carbon (TOC) ( approximately 1-2%) and JS1 sequences were abundant. In contrast, the deeper sandy layers of Gröninger Plate, despite also having reduced sulphate concentrations, had lower TOC (<0.6%) with few detectable JS1 sequences. Results indicated that JS1 prefers muddy, shallow, subsurface sediments with reduced sulphate, whereas Chloroflexi may out-compete JS1 in shallow, sandy, subsurface sediments. Bacterial population changes at both sites ( approximately 2 m) were confirmed by cluster analysis of DGGE profiles, which correlated with increased recalcitrance of the organic matter. This study extends the biogeographical range of JS1. The presence of JS1 and Chloroflexi in Wadden Sea sediments demonstrates that subsurface tidal flats contain similar prokaryotic populations to those found in the deeper subseafloor biosphere.

A highly sensitive HPLC method for determination of nanomolar concentrations of dipicolinic acid, a characteristic constituent of bacterial endospores.

A high-performance liquid chromatographic method with indirect fluorescence detection has been developed for quantification of dipicolinic acid, a major constituent of bacterial endospores. After separation on a reversed-phase column, a post-column reagent of sodium acetate at 1 mol l(-1) with 50 micromol l(-1) terbium chloride was added for complexation of dipicolinic acid. Terbium monodipicolinate complexes formed were quantified by measuring the fluorescence emission maximum at 548 nm after excitation with UV light at 270 nm wavelength. Parameters of post-column complexation were optimized to achieve a detection limit of 0.5 nmol DPA l(-1), corresponding to about 10(3) Desulfosporosinus orientis endospores per ml. The method was applied to the analysis of spore contamination in tuna and for estimating the endospore numbers in marine sediments.

The angiotensin II receptor antagonist telmisartan reduces urinary albumin excretion in patients with isolated systolic hypertension: results of a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To examine the effect of telmisartan or hydrochlorothiazide on the control of urinary albumin excretion (UAE) in patients with isolated systolic hypertension (ISH) unselected for albuminuria in a pre-planned substudy of a large, multicentre, double-blind, placebo-controlled, randomized study. METHODS: The Angiotensin II Receptor Antagonist Micardis in Isolated Systolic hypertension (ARAMIS) study compared the antihypertensive efficacy after 6 weeks of once-daily fixed doses of telmisartan 20, 40 or 80 mg versus hydrochlorothiazide 12.5 mg or placebo in patients (n = 1039, aged 35-84 years) with ISH (seated blood pressure 150-179/< 90 mmHg). The prospective substudy analysed UAE using spot morning samples. RESULTS: Urinary albumin (> 2.2-901.6 mg/l) was detected at baseline in 614 out of 918 patients who were included in the substudy analysis. In the telmisartan group (n = 354, all doses combined), a median reduction in UAE from a baseline of 14.1% [95% confidence interval (CI) 7.3, 21.8] was observed versus 1.1% (95% CI -13.5 to 16.0) and 2.7% (95% CI -0.9 to 19.9) in the hydrochlorothiazide (n = 140) and placebo (n = 120) groups, respectively. The difference between telmisartan and hydrochlorothiazide was significant (P = 0.017). Reductions in UAE with telmisartan were observed in patients with baseline normoalbuminuria, microalbuminuria or macroalbuminuria. Telmisartan and hydrochlorothiazide produced comparable reductions in systolic blood pressure in these patients. CONCLUSION: In patients with ISH unselected for baseline albuminuria, telmisartan 20-80 mg after 6 weeks' treatment afforded significantly greater lowering of UAE than hydrochlorothiazide 12.5 mg, irrespective of the baseline UAE, and despite comparable reductions in systolic blood pressure with both drugs.

Angiotensin II receptor antagonist telmisartan in isolated systolic hypertension (ARAMIS) study: efficacy and safety of telmisartan 20, 40 or 80 mg versus hydrochlorothiazide 12.5 mg or placebo.

OBJECTIVE: To identify telmisartan doses that are more effective than placebo and non-inferior to hydrochlorothiazide (HCTZ) 12.5 mg, and are well tolerated, in lowering systolic blood pressure (SBP) in patients with isolated systolic hypertension (ISH). PATIENTS AND METHODS: A 2-4-week single-blind placebo run-in was followed by randomization of 1039 patients (age 36-84 years) with ISH [seated SBP 150-179 mmHg and seated diastolic blood pressure (DBP) < 90 mmHg] to once-daily double-blind treatment with telmisartan 20, 40 or 80 mg, HCTZ 12.5 mg, or placebo. The change in seated trough SBP after 6 weeks compared with baseline was the primary end point. Secondary end points were the percentage achieving the target fall in SBP and the change from baseline in seated trough DBP. Incidence and severity of adverse events and physical examination and laboratory parameters were monitored for the safety evaluation. RESULTS: Baseline demographics in telmisartan 20 mg (n = 206), 40 mg (n = 210), 80 mg (n = 207), HCTZ 12.5 mg (n = 205) and placebo (n = 211) treatment groups were comparable: (mean +/- SD) age, 63.0 +/- 10.9 years; SBP, 162.9 +/- 8.1 mmHg; and DBP 83.4 +/- 5.0 mmHg. No previous antihypertensive therapy had been received by 66% of the patients. Mean reductions in seated trough SBP (adjusted for baseline and country) were: telmisartan 20 mg, 15.6 mmHg (n = 204); 40 mg, 17.9 mmHg (n = 209); and 80 mg, 16.9 mmHg (n = 205), compared with placebo, 11.4 mmHg (n = 208), and HCTZ 12.5 mg, 15.7 mmHg (n = 204). The target fall in seated trough SBP (< or =140 mmHg or reduction by > or =20 mmHg) was achieved in 46.6% (telmisartan 20 mg), 51.7% (telmisartan 40 mg), 53.9% (telmisartan 80 mg), 27.4% (placebo) and 42.7% (HCTZ 12.5 mg); the response rate was significantly higher for telmisartan 80 mg than for HCTZ 12.5 mg (P = 0.03). All-causality adverse events occurred in 19.9, 17.6 and 20.3% receiving telmisartan 20, 40 and 80 mg, respectively; 20.9% receiving placebo and 22.0% receiving HCTZ 12.5 mg. No drug-related serious adverse events occurred. CONCLUSIONS: All doses of telmisartan (20-80 mg) were significantly superior to placebo in reducing SBP in patients with ISH and clinically comparable to HCTZ 12.5 mg. Tolerability of telmisartan was similar to that of placebo.

Pramipexole in routine clinical practice: a prospective observational trial in Parkinson's disease.

OBJECTIVE: The mixed dopamine D2/D3 receptor agonist pramipexole is effective as monotherapy in early Parkinson's disease and as adjunctive therapy in advanced disease. Clinical trials suggest that the benefits of pramipexole may extend beyond the relief of motor symptoms (akinesia, rigidity and tremor at rest) to amelioration of depressive symptoms in Parkinson's disease. The aim of this study was to confirm the beneficial effects of pramipexole on the core symptoms of Parkinson's disease (with a focus on tremor), as well as to assess its antidepressant activity, during routine clinical practice. The study also aimed to demonstrate the practicability of the Snaith-Hamilton Pleasure Scale (SHAPS-D), the Tremor Impact Scale (TIS) and the Short Parkinson's Evaluation Scale (SPES) under conditions of routine clinical practice. STUDY DESIGN: This was a prospective observational study. PATIENTS: Data for 657 outpatients with Parkinson's disease were collected from German hospitals and specialist practices. The majority of patients were in Hoehn & Yahr stage II or III and were receiving levodopa. METHODS: Pramipexole (Sifrol) was initiated at a dosage of 0.375 mg/day (using a three-times-daily schedule) and titrated upwards, as required, at weekly intervals over a 4-week period to a maximum dosage of 4.5 mg/day (three times daily). Clinical evaluation was performed at baseline, at the end of the titration phase and at the end of maintenance therapy. Patients were assessed via the German questionnaire versions of the physician-assessed SPES, the self-evaluated TIS and the SHAPS-D. Changes in scale scores were evaluated nonparametrically, using the Wilcoxon-matched pairs test. Cronbach's alpha was used as a measure for item consistency. RESULTS: Pramipexole significantly improved SPES subscores for motor symptoms, complications of therapy, psychological status and activities of daily living. Pramipexole also reduced the detrimental effect of tremor on activities of daily living and social interactions, as assessed by patients via the TIS. As indicated by the results of the SHAPS-D questionnaire, pramipexole significantly reduced anhedonia in patients who had associated depression. Internal consistency of SPES subscales was found to be unaltered between the initial evaluation and follow-up. Likewise, internal consistency for TIS and SHAPS-D was demonstrated. Pramipexole was well tolerated and accepted by the vast majority of physicians and patients. CONCLUSION: In addition to ameliorating the core symptoms of akinesia and rigidity in Parkinson's disease, pramipexole improves tremor and depressive symptoms in routine clinical practice. The SPES, TIS and SHAPS-D were found to be useful instruments with validity in this study.

Safety of telmisartan in patients with arterial hypertension : an open-label observational study.

OBJECTIVE: To determine whether age, gender, concomitant disease and/or previous or present antihypertensive medication affect the safety or antihypertensive efficacy of telmisartan in the treatment of arterial hypertension. STUDY DESIGN AND METHODS: In this large-scale, open-label postmarketing surveillance study, German physicians systematically documented their observations concerning patients with essential hypertension on case report forms. Patients were treated for 6 months with telmisartan (40-80 mg once daily). Data were analysed using direct group comparisons and multiple linear regression analysis. RESULTS: A total of 19 870 patients (52.3% males, mean age 59.1 years) were evaluated, of whom 47.6, 18.3, 13.2 and 2.1%, respectively, had concomitant hypercholesterolaemia, diabetes mellitus, congestive heart failure and renal insufficiency. In the overall group, adverse events were reported in 1.9% of patients. Global tolerability was rated as very good, good, moderate or poor, respectively, in 74.7, 22.1, 0.7 and 0.5% of patients; tolerability was similar across all subgroups of patients. Telmisartan treatment did not increase serum creatinine or potassium in any subgroup, including >400 patients with impaired renal function (basal creatinine 1.73 mg/dL). Telmisartan had no adverse effects on glucose, triglyceride or cholesterol levels. In the overall group, telmisartan reduced mean +/- SD systolic blood pressure from 171.3 +/- 16.4 mm Hg to 141.3 +/- 12.0 mm Hg and diastolic blood pressure from 99.0 +/- 9.4 mm Hg to 83.4 +/- 6.9 mm Hg. Reductions were very similar between genders, age groups and patients with and without comorbidities, and not dependent on prior or concomitant treatment with other antihypertensive drugs. CONCLUSION: The safety and efficacy of telmisartan found in controlled studies is maintained in a large postmarketing population that included sizeable patient subgroups potentially at higher risk for adverse events.

Differential diagnosis of unpleasant sensations in the legs: prevalence of restless legs syndrome in a primary care population.

BACKGROUND: Restless legs syndrome (RLS) is a common neurological condition. We investigated the prevalence of RLS in patients suffering from unpleasant sensations in the legs. METHODS: We included 16,543 patients consulting one of 312 primary care practices in Germany on November 8, 2007. All patients filled out a self-assessment questionnaire. Patients who reported suffering from unpleasant sensations in the legs were then assessed by the physician. Main outcome measures were the overall prevalence of unpleasant sensations in the legs and the prevalence of RLS; the most common differential diagnoses in the subpopulation suffered from unpleasant leg sensations. RESULTS: Out of all participating patients 7704 (46.6%) suffered from unpleasant sensations in the legs and 1758 (10.6%) were diagnosed with RLS according to the four essential clinical criteria. Among patients with unpleasant leg sensations, the prevalence of RLS was considerably higher (22.7%) than in the total population. The most common differential diagnoses were osteoarthritis (21.5%), disc lesion (19.2%), varicose veins (18.8%) and muscle cramps (14.6%). Of the patients with RLS 53.4% had already consulted their physician about their leg problems in the past. Still, only 20.1% of the RLS patients had received the correct diagnosis. Comorbidity rates were significantly increased in RLS patients compared to patients suffering from leg symptoms of other origin. CONCLUSIONS: This study showed a high prevalence of RLS in primary care patients with unpleasant sensations in the legs. Thus, in patients presenting with these symptoms the diagnosis of RLS should routinely be considered.

Comparison of three disposable extraglottic airway devices in spontaneously breathing adults: the LMA-Unique, the Soft Seal laryngeal mask, and the Cobra perilaryngeal airway.

BACKGROUND: The authors compared three disposable extraglottic airway devices in spontaneously breathing anesthetized adults: the LMA-Unique (LMA-U; The Laryngeal Mask Company, San Diego, CA), the Soft Seal laryngeal mask (SS-LM; Portex Ltd., Hythe, United Kingdom), and the Cobra perilaryngeal airway (Cobra-PLA; Engineered Medical Systems, Inc. Indianapolis, IN). METHODS: Three hundred twenty consecutive adults (American Society of Anesthesiologists physical status I-III; aged 18-80 yr) were randomly allocated for airway management with one of the three devices. Anesthesia was with fentanyl-propofol for induction and a sevoflurane-nitrous oxide-oxygen-fentanyl mixture for maintenance. Intraoperative data were collected by an unblinded observer about ease of insertion, effective airway time, oropharyngeal leak pressure, anatomical position (determined with a rigid endoscope), intracuff pressure changes, and airway trauma. Data were collected by a blinded observer about sore throat, dysphagia, and dysphonia 2 h after surgery. RESULTS: Insertion was easier with the LMA-U and SS-LM than with the Cobra-PLA (P < 0.02), but the overall failure rates were similar. Effective airway times were similar among groups. Oropharyngeal leak pressure was lower with the LMA-U than with the SS-LM and Cobra-PLA (P < 0.001). Intracuff pressure increased during surgery with all extraglottic airway devices. Anatomical position was better with the Cobra-PLA than with the SS-LMA (P < 0.001) and better with the SS-LM than with LMA-U (P < 0.001). Blood staining was detected more frequently with the Cobra-PLA than with the LMA-U and SS-LM (P < 0.001), but there were no differences in airway morbidity. CONCLUSION: The LMA-U and SS-LM are easier to insert and cause less trauma than the Cobra-PLA, but the Cobra-PLA has a more effective seal than the LMA-U and better endoscopically determined anatomical position than the LMA-U and SS-LM.

Specific bacterial, archaeal, and eukaryotic communities in tidal-flat sediments along a vertical profile of several meters.

The subsurface of a tidal-flat sediment was analyzed down to 360 cm in depth by molecular and geochemical methods. A community structure analysis of all three domains of life was performed using domain-specific PCR followed by denaturing gradient gel electrophoresis analysis and sequencing of characteristic bands. The sediment column comprised horizons easily distinguishable by lithology that were deposited in intertidal and salt marsh environments. The pore water profile was characterized by a subsurface sulfate peak at a depth of about 250 cm. Methane and sulfate profiles were opposed, showing increased methane concentrations in the sulfate-free layers. The availability of organic carbon appeared to have the most pronounced effect on the bacterial community composition in deeper sediment layers. In general, the bacterial community was dominated by fermenters and syntrophic bacteria. The depth distribution of methanogenic archaea correlated with the sulfate profile and could be explained by electron donor competition with sulfate-reducing bacteria. Sequences affiliated with the typically hydrogenotrophic Methanomicrobiales were present in sulfate-free layers. Archaea belonging to the Methanosarcinales that utilize noncompetitive substrates were found along the entire anoxic-sediment column. Primers targeting the eukaryotic 18S rRNA gene revealed the presence of a subset of archaeal sequences in the deeper part of the sediment cores. The phylogenetic distance to other archaeal sequences indicates that these organisms represent a new phylogenetic group, proposed as "tidal-flat cluster 1." Eukarya were still detectable at 360 cm, even though their diversity decreased with depth. Most of the eukaryotic sequences were distantly related to those of grazers and deposit feeders.

Long-term efficacy and safety of pramipexole in advanced Parkinson's disease: results from a European multicenter trial.

A double-blind, placebo-controlled study with a subsequent open-label phase was conducted in 354 patients with Parkinson's disease (PD) and motor fluctuations under individually adjusted therapy with levodopa. During the double-blind phase 174 patients received pramipexole and 180 placebo. In agreement with previous studies, pramipexole treatment improved UPDRS sum scores of parts II and III by 30% and off times by approximately 2.5 hours per day. Differences between the treatment groups became significant at a daily dose of 0.75 mg of pramipexole dihydrochloride. We, furthermore, performed post hoc analyses with respect to resting tremor and depression. Patients with pronounced resting tremor derived a clear benefit from pramipexole treatment compared with placebo. In addition, pramipexole significantly improved the subitems motivation/initiative and depression in a subpopulation with increased Unified Parkinson's Disease Rating Scale I scores at the time of inclusion. There were 262 patients who were subsequently enrolled into the open-label study featuring a maximum duration of up to 57 months. Statistical analysis revealed good long-term efficacy and tolerability of pramipexole. Overall, only a low prevalence of somnolence was found. In summary, this study provides additional level I evidence of the usefulness of pramipexole, suggests a particular tremorlytic and a possible antidepressant action of this compound, and addresses for the first time its efficacy and safety during long-term administration in advanced PD.

Degradation of petroleum model compounds immobilized on clay by a hypersaline microbial mat.

In this study the degradation of hydrophobic petroleum model compounds (phenanthrene, pristane, octadecane and dibenzothiophene) added to a submersed hypersaline microbial mat was investigated. Montmorillonite with an artificially altered, hydrophobic surface was used as carrier material, forming an organo-clay complex (OCC) with the attached mixture of petroleum model compounds. 6 mg/cm2 OCC were applied to cyanobacterial mat pieces, containing approximately 33.3 microg/mg OCC of each compound. The degradation experiment was performed under controlled laboratory conditions and accompanied by chemical analyses by GC/GC-MS, molecular analyses by PCR and DGGE as well as functional analyses by microsensor measurements of oxygen, photosynthesis, sulfide, pH and light. All applied model compounds were degraded, but residues were still present after 18 weeks. The aromatic compounds phenanthrene (5.1 microg/mg OCC) and dibenzothiophene (4.3 microg/mg OCC) were preferentially degraded compared to the alkanes pristane (12.4 microg/mg OCC) and n-octadecane (13.4 microg/mg OCC). Metabolic changes during the degradation process could not be detected by microsensor measurements. The molecular population analyses did not reveal any significant community changes concomitant with the decrease of the petroleum model compounds. We conclude, that the pristine mats represent an intact, robust ecosystem in which the enzymatic requirements for the degradation of the applied pollutants exist. The slow degradation process did not affect the usual high internal turnover rates and did not favor a certain population in the community of the mats.

Sleep attacks, daytime sleepiness, and dopamine agonists in Parkinson's disease.

To study the putative association of dopamine agonists with sleep attacks in patients with Parkinson's disease (PD) and their relation to daytime sleepiness, we performed a survey of 2,952 PD patients in two German counties. In 177 patients, sudden, unexpected, and irresistible sleep episodes while engaged in some activity were identified in a structured telephone interview. Ninety-one of these patients denied the occurrence of appropriate warning signs. A total of 133 patients (75%) had an Epworth Sleepiness Scale (ESS) score >10; 65 (37%) >15. Thirty-one patients (18%) had an ESS score < or =10 and yet experienced sleep attacks without warning signs. Thus, although a significant proportion of patients at risk for sleep attacks might be identified using the ESS, roughly 1% of the PD patient population seems to be at risk for sleep attacks without appropriate warning signs and without accompanying daytime sleepiness. Sleep attacks occurred with all dopamine agonists marketed in Germany (alpha-dihydroergocryptine, bromocriptine, cabergoline, lisuride, pergolide, pramipexole, ropinirole), and no significant difference between ergot and nonergot drugs was evident. Levodopa (L-dopa) monotherapy carried the lowest risk for sleep attacks (2.9%; 95% confidence interval [CI], 1.7-4.0%) followed by dopamine agonist monotherapy (5.3%; 95% CI, 1.5-9.2%) and combination of L-dopa and a dopamine agonist (7.3%; 95% CI, 6.1-8.5%). Neither selegeline nor amantadine or entacapone appeared to influence the occurrence of sleep attacks. A high ESS score, intake of dopamine agonists, and duration of PD were the main influencing factors for the occurrence of sleep attacks. The odds ratio for dopamine agonist therapy was 2.9 compared to 1.9 with L-dopa therapy and 1.05 for a 1-year-longer disease duration.

Microbial diversity of a heavily polluted microbial mat and its community changes following degradation of petroleum compounds.

We studied the microbial diversity of benthic cyanobacterial mats inhabiting a heavily polluted site in a coastal stream (Wadi Gaza) and monitored the microbial community response induced by exposure to and degradation of four model petroleum compounds in the laboratory. Phormidium- and Oscillatoria-like cyanobacterial morphotypes were dominant in the field. Bacteria belonging to different groups, mainly the Cytophaga-Flavobacterium-Bacteriodes group, the gamma and beta subclasses of the class Proteobacteria, and the green nonsulfur bacteria, were also detected. In slurry experiments, these communities efficiently degraded phenanthrene and dibenzothiophene completely in 7 days both in the light and in the dark. n-Octadecane and pristane were degraded to 25 and 34% of their original levels, respectively, within 7 days, but there was no further degradation until 40 days. Both cyanobacterial and bacterial communities exhibited noticeable changes concomitant with degradation of the compounds. The populations enriched by exposure to petroleum compounds included a cyanobacterium affiliated phylogenetically with Halomicronema. Bacteria enriched both in the light and in the dark, but not bacteria enriched in any of the controls, belonged to the newly described Holophaga-Geothrix-Acidobacterium phylum. In addition, another bacterial population, found to be a member of green nonsulfur bacteria, was detected only in the bacteria treated in the light. All or some of the populations may play a significant role in metabolizing the petroleum compounds. We concluded that the microbial mats from Wadi Gaza are rich in microorganisms with high biodegradative potential.