Multiple-mouse magnetic resonance imaging with cryogenic radiofrequency probes for evaluation of brain development.

Multiple-mouse magnetic resonance imaging (MRI) increases scan throughput by imaging several mice simultaneously in the same magnet bore, enabling multiple images to be obtained in the same time as a single scan. This increase in throughput enables larger studies than otherwise feasible and is particularly advantageous in longitudinal study designs where frequent imaging time points result in high demand for MRI resources. Cryogenically-cooled radiofrequency probes (CryoProbes) have been demonstrated to have significant signal-to-noise ratio benefits over comparable room temperature coils for in vivo mouse imaging. In this work, we demonstrate implementation of a multiple-mouse MRI system using CryoProbes, achieved by mounting four such coils in a 30-cm, 7-Tesla magnet bore. The approach is demonstrated for longitudinal quantification of brain structure from infancy to early adulthood in a mouse model of Sanfilippo syndrome (mucopolysaccharidosis type III), generated by knockout of the Hgsnat gene. We find that Hgsnat-/- mice have regionally increased growth rates compared to Hgsnat+/+ mice in a number of brain regions, notably including the ventricles, amygdala and superior colliculus. A strong sex dependence was also noted, with the lateral ventricle volume growing at an accelerated rate in males, but several structures in the brain parenchyma growing faster in females. This approach is broadly applicable to other mouse models of human disease and the increased throughput may be particularly beneficial in studying mouse models of neurodevelopmental disorders.

Thyroid hormone-dependent formation of a subcortical band heterotopia (SBH) in the neonatal brain is not exacerbated under conditions of low dietary iron (FeD).

Thyroid hormones (TH) are critical for brain development and insufficiencies can lead to structural abnormalities in specific brain regions. Administration of the goitrogen propylthiouracil (PTU) reduces TH production by inhibiting thyroperoxidase (TPO), an enzyme that oxidizes iodide for the synthesis of TH. TPO activity is iron (Fe)-dependent and dietary iron deficiency (FeD) also reduces circulating levels of TH. We have previously shown that modest degrees of TH insufficiency induced in pregnant rat dams alters the expression of TH-responsive genes in the cortex and hippocampus of the neonate, and results in the formation of a subcortical band heterotopia (SBH) in the corpus callosum (Royland et al., 2008, Bastian et al., 2014, Gilbert et al., 2014). The present experiment investigated if FeD alone was sufficient to induce a SBH or if FeD would augment SBH formation at lower doses of PTU. One set of pregnant rats was administered 0, 1, 3, or 10ppm of PTU via drinking water starting on gestational day (GD) 6. FeD was induced in a 2nd set of dams beginning on GD2. A third set of dams received the FeD diet from GD2 paired with either 1ppm or 3ppm PTU beginning on GD6. All treatments continued until the time of sacrifice. On PN18, one female pup from each litter was sacrificed and the brain examined for SBH. We observed lower maternal, PN2 and PN18 pup serum T4 in response to PTU. FeD reduced serum T4 in pups on PN16, but did not affect serum T4 in dams or PN2 pups. Neither did FeD in combination with PTU alter T4 levels in dams on PN18 or pups on PN2 compared to PTU treatment alone. By PN16, however more severe T4 reductions were observed in pups when FeD was combined with PTU. SBH increased with increasing dosage of PTU, but counter to our hypothesis, no SBH was detected in the offspring of FeD dams. As such, T4 levels in dams and newborn pups rather than older neonates appear to be a better predictor SBH associated with TH insufficiency. These data indirectly support previous work indicating prenatal TH insufficiency but not postnatal TH insufficiency in offspring is required for SBH formation.

C-reactive protein as a marker of complicated diverticulitis in patients on anti-inflammatory medications.

BACKGROUND: Diverticulitis is a common indication for surgical emergency room admission, often leading to abdominal computed tomography (CT) scanning for both diagnosis and staging. C-reactive protein (CRP) has been identified as a useful biomarker of inflammation. Aspirin and corticosteroids are known to down-regulate CRP production. In this study, we evaluated the usefulness of CRP as a biomarker for complicated diverticulitis and specifically in patients on anti-inflammatory medications: aspirin and corticosteroids. METHODS: We analyzed the medical records of patients diagnosed at one medical center during a two-year period, with left-sided diverticulitis, according to clinical data and CT scan. Disease severity was assessed by the Hinchey score using the radiological findings detected by CT. RESULTS: A total of 295 patients were included in the study. Two hundred and forty-three (82 %) were classified with uncomplicated (Hinchey 1a) and 52 (18 %) with complicated disease (Hinchey > 1a). Mean CRP levels were 133.5 and 63.5 mg/ml for those with complicated and uncomplicated disease, respectively (p < 0.001), and 139 and 60 mg/ml, respectively (p < 0.001) in the subgroup of patients taking aspirin (n = 61). For 14 patients on corticosteroid treatment, the difference in mean CRP levels for complicated and uncomplicated disease was not statistically significant. CRP > 90 mg/ml had 88 % sensitivity and 75 % specificity for complicated disease. CONCLUSIONS: The CRP level distinguished between complicated and uncomplicated disease among left-sided diverticulitis patients including those taking aspirin, but not among those on corticosteroid treatment.

Influence of plaque volume on hemodynamic response and stress hormone release in patients undergoing carotid artery stenting.

AIM: Carotid artery stenting (CAS) may cause bradycardia and hypotension due to barostimulation. The impact of periprocedural hypotension on CAS outcome remains controversial. The role of carotid plaque volume and catecholamine hormone release during CAS on hemodynamic changes has not been investigated so far. The aim of this prospective study was to evaluate if carotid artery plaque characteristics are predictive for stress hormone release or for postprocedural hemodynamic instability. METHODS: In 26 patients undergoing CAS, carotid plaque volume and morphology were assessed by two- and three-dimensional (3D)-Duplex sonography prior to the procedure. Arterial plasma adrenaline, noradrenaline and renin concentrations were measured at the time of sheath insertion and 5 minutes after stent placement. ECG, heart rate, and invasive blood pressure were monitored throughout the procedure. RESULTS: CAS caused no significant changes in hormone release, but increasing plaque volume was related to the degree of bradycardia following stent deployment (r=0.57; P=0.01). Plaque size was not associated with postprocedural hypotension. Plaque echogenicity (echolucent, heterogeneous or echogenic) did not correlate with changes in systolic blood pressure, heart rate or catecholamine hormone release. CONCLUSION: CAS caused bradycardia in relation to plaque size, but did not cause catecholamine release which may indicate that the endovascular procedure is not associated with a relevant stress reaction.

Successful reduction of clinical relevant neovascularization with a modified crossectomy combined with a barrier technique after 10-year follow-up.

OBJECTIVE: The aim of this retrospective study was to assess the long-term results of stripping the insufficient great saphenous vein (GSV) with stump coagulation, closure of the cribriform fascia and some additional measures, which will be described in detail. METHODS: Patients treated from 1998 to 1999 for varicose veins had been invited in 2009 for follow-up colour-coded duplex sonography and had been asked to answer a quality-of-life questionnaire. In 2009, the examinations for the study were conducted at a clinic of angiology by an independent and experienced sonographer. RESULTS: From a total of 165 patients, 91 (136 limbs) had been willing to participate in the study. Duplex ultrasound after a mean follow-up of 10.7 years revealed only clinically non-relevant (∅ < 0.3 cm) neovascularizations in 1.5% of all treated legs. No clinical relevant varicosities from the groin had developed. CONCLUSION: The crossectomy combined with stump coagulation and suture of the fossa ovalis, completed with some additional measures, is a successful method to reduce neovascularization and recurrent varicosities, even for redo-crossectomies, without increasing the risk of perioperative complications.

Desulfovibrio idahonensis sp. nov., sulfate-reducing bacteria isolated from a metal(loid)-contaminated freshwater sediment.

Two novel sulfate-reducing bacteria, strains CY1T and CY2, were isolated from heavy-metal-contaminated sediments of Lake Coeur d'Alene, Idaho, USA. Strains CY1T and CY2 were found to contain c-type cytochromes and to reduce sulfate, sulfite, thiosulfate, elemental sulfur, DMSO, anthraquinone disulfonate and fumarate using lactate as an electron donor. In a comparison of 16S rRNA gene sequences, CY1T and CY2 were found to be 100% identical, but only 97 and 92.4% similar, respectively, to the type strains of Desulfovibrio mexicanus and Desulfovibrio aminophilus. Unlike these species, however, CY1T was neither able to disproportionate thiosulfate nor able to use yeast extract or amino acids as electron donors. These data, considered in conjunction with differences among strain CY1T and the two related type strains in chemotaxonomy, riboprint patterns, temperature and pH optima, support recognition of a distinct and novel species within the genus Desulfovibrio, Desulfovibrio idahonensis sp. nov., with the type strain CY1T (=DSM 15450T=JCM 14124T).

Lack of major gender-related differences in patients undergoing elective endovascular or surgical repair of abdominal aortic aneurysm.

AIM: The aim of this single center retrospective study was to determine gender-related differences in patients undergoing repair of aortic aneurysm. METHODS: A total of 296 consecutive patients with an abdominal aneurysm undergoing elective endovascular or surgical repair was included in the study. Among these, 24 (8.1%) were females and 272 (91.9%) were males. Demographic and clinical characteristics as well as laboratory values in terms of any potential gender-specific differences were compared. RESULTS: Females were significantly older at the time of repair than males. No gender-related differences were found analysing major clinical and laboratory parameters. CONCLUSIONS: The clinical and laboratory profile with which males and females present at the time of elective endovascular or surgical repair for aortic aneurysm is very similar. It does not reveal any potential gender-specific risk constellation. It eventually remains unclear why the prevalence of aortic aneurysm is higher in male than in females.

Wall shear rate in supra-aortic vessels: a factor for different atherosclerotic pattern?

BACKGROUND: Atherosclerotic lesions of the upper extremity arise three to five times more often at the origin of the left subclavian artery than on the right side. The aim of this study was to investigate, whether the hemodynamic forces (peak wall shear rate) in the large supra-aortic branches measured by MRI differ in healthy subjects. PATIENTS AND METHODS: Peak wall shear rate (WSR) and blood flow was assessed in the left carotid, left subclavian and innominate artery in ten healthy volunteers (5 females, mean age of 35.2 +/- 9 years) using high resolution (pixel size 0.6 mm 2) magnetic resonance imaging (MRI) flow velocity measurements. RESULTS: There is no difference between the maximum WSR of the three large supra-aortic vessels. Only within the proximal (327 +/- 132s-1) and distal wall (458 +/- 154s-1) of the innominate artery a significant difference (p = 0.011) of the WSR was found. CONCLUSION: The results from this study indicate that WSR is not different in the supra-aortic vessels. Therefore the atherosclerotic pattern in the subclavian and innominate arteries may not be explained by differences in these hemodynamic forces.

High resolution three-dimensional brain atlas using an average magnetic resonance image of 40 adult C57Bl/6J mice.

Detailed anatomical atlases can provide considerable interpretive power in studies of both human and rodent neuroanatomy. Here we describe a three-dimensional atlas of the mouse brain, manually segmented into 62 structures, based on an average of 32 mum isotropic resolution T(2)-weighted, within skull images of forty 12 week old C57Bl/6J mice, scanned on a 7 T scanner. Individual scans were normalized, registered, and averaged into one volume. Structures within the cerebrum, cerebellum, and brainstem were painted on each slice of the average MR image while using simultaneous viewing of the coronal, sagittal and horizontal orientations. The final product, which will be freely available to the research community, provides the most detailed MR-based, three-dimensional neuroanatomical atlas of the whole brain yet created. The atlas is furthermore accompanied by ancillary detailed descriptions of boundaries for each structure and provides high quality neuroanatomical details pertinent to MR studies using mouse models in research.

Desulfosporosinus hippei sp. nov., a mesophilic sulfate-reducing bacterium isolated from permafrost.

The sulfate-reducing strain 343T was isolated from ancient permafrost deposits in Siberia, Russia. Based on 16S rRNA gene sequence analyses, this strain was closely related to Desulfosporosinus species, showing 97.9 % 16S rRNA gene sequence similarity to Desulfosporosinus meridiei DSM 13257T, 97.6 % similarity to Desulfosporosinus auripigmenti DSM 13351T, 97.2 % similarity to Desulfosporosinus lacus DSM 15449T and 96.2 % similarity to Desulfosporosinus orientis DSM 765T. The strain was found to contain b-type cytochromes and to reduce only sulfate and thiosulfate using lactate as an electron donor but not sulfite, elemental sulfur, fumarate, nitrate or Fe(III). These data, considered in conjunction with DNA-DNA hybridization data, cell-wall chemotaxonomy and data on physiology, support recognition of strain 343T as representing a distinct and novel species within the genus Desulfosporosinus, namely Desulfosporosinus hippei sp. nov., with the type strain 343T (=DSM 8344T =VKM B-2003T).

Desulfosporosinus lacus sp. nov., a sulfate-reducing bacterium isolated from pristine freshwater lake sediments.

A novel sulfate-reducing bacterium was isolated from pristine sediments of Lake Stechlin, Germany. This strain, STP12(T), was found to contain predominantly c-type cytochromes and to reduce sulfate, sulfite and thiosulfate using lactate as an electron donor. Although STP12(T) could not utilize elemental sulfur as an electron acceptor, it could support growth by dissimilatory Fe(III) reduction. In a comparison of 16S rRNA gene sequences, STP12(T) was 96.7 % similar to Desulfosporosinus auripigmenti DSM 13351(T), 96.5 % similar to Desulfosporosinus meridiei DSM 13257(T) and 96.4 % similar to Desulfosporosinus orientis DSM 765(T). DNA-DNA hybridization experiments revealed that strain STP12(T) shows only 32 % reassociation with the type strain of the type species of the genus, D. orientis DSM 765(T). These data, considered in conjunction with strain-specific differences in heavy metal tolerance, cell-wall chemotaxonomy and riboprint patterns, support recognition of strain STP12(T) (=DSM 15449(T)=JCM 12239(T)) as the type strain of a distinct and novel species within the genus Desulfosporosinus, Desulfosporosinus lacus sp. nov.

Vulcanibacillus modesticaldus gen. nov., sp. nov., a strictly anaerobic, nitrate-reducing bacterium from deep-sea hydrothermal vents.

A novel anaerobic, moderately thermophilic, spore-forming bacterium, designated strain BRT, was isolated from deep-sea hydrothermal core samples collected at the Rainbow vent field on the Mid-Atlantic Ridge (36 degrees 14' N 33 degrees 54' W). The cells were found to be rod-shaped, non-motile, Gram-positive and spore-forming. The organism grew in the temperature range 37-60 degrees C, with an optimum at 55 degrees C, and at pH values in the range 6-8.5, with an optimum around pH 7. NaCl concentrations for growth were in the range 10-40 g l(-1), with an optimum at 20-30 g l(-1). Strain BRT grew chemo-organoheterotrophically with carbohydrates, proteinaceous substrates and organic acids with nitrate as electron acceptor. The novel isolate was not able to ferment. The G+C content of the genomic DNA was 34.5 mol%. Phylogenetic analysis of the 16S rRNA gene sequence placed strain BRT in the Bacillaceae within the class 'Bacilli'. On the basis of the phenotypic and phylogenetic data, this isolate should be described as a member of a novel genus, for which the name Vulcanibacillus gen. nov. is proposed. The type species is Vulcanibacillus modesticaldus sp. nov., with the type strain BRT (=DSM 14931T=JCM 12998T).

Carotid intima-media thickness, carotid wall shear stress and restenosis after femoro-popliteal percutaneous transluminal angioplasty (PTA).

OBJECTIVE: To determine the relationship between carotid intima-media thickness (IMT), carotid wall shear stress (WSS) and restenosis after femoro-popliteal percutaneous transluminal angioplasty (PTA). PATIENTS AND METHODS: Thirty-one subjects (18 men, 13 women, median age 69 years) treated with femoro-popliteal PTA for symptomatic peripheral arterial occlusive disease were enrolled. On admission, IMT, internal diameter and blood velocity of the common carotid artery (CCA) were assessed by high-resolution ultrasonography. Blood viscosity was measured and carotid WSS was calculated. Patients were followed up for 6 months for the occurrence of significant restenosis (>50%) as documented by duplex ultrasonography. Two patients were lost to follow-up. RESULTS: Fourteen patients (48%) developed restenosis at 6 months. IMT and WSS were not different in patients without and with restenosis (IMT: 0.90 (0.85-0.97) vs. 0.89 (0.84-0.93) mm, p = 0.51; WSS: 14.1 (11.9-19.2) vs. 15.9 (12.8-21.5) dyne/cm2, p = 0.48). The hazard ratio of incident restenosis as estimated by Cox regression analysis was 0.04 for IMT (p = 0.23; 95% CI 0.0001-8.22) and 1.07 for WSS (p = 0.10; 95% CI 0.98-1.17). CONCLUSIONS: In this pilot study involving a limited number of patients, carotid IMT and carotid WSS are not significantly related to restenosis at 6 months after femoro-popliteal PTA. This might be the result of different underlying pathophysiology for atherosclerosis and restenosis.

Caminibacter profundus sp. nov., a novel thermophile of Nautiliales ord. nov. within the class 'Epsilonproteobacteria', isolated from a deep-sea hydrothermal vent.

A novel moderately thermophilic, microaerobic to anaerobic, chemolithoautotrophic bacterium, designated strain CRT, was isolated from a deep-sea hydrothermal vent site at 36 degrees N on the Mid-Atlantic Ridge. Cells were Gram-negative, non-motile rods. The organism grew at 45-65 degrees C and pH 6.5-7.4, with optimum growth at 55 degrees C and pH 6.9-7.1. The NaCl range for growth was 5-50 g l(-1) (optimum 30 g l(-1)). Strain CRT was an obligate chemolithoautotroph, growing with H2 as energy source, sulfur, nitrate or oxygen as electron acceptors and CO2 as carbon source. Hydrogen sulfide and ammonium were the respective products of sulfur and nitrate reduction. The G+C content of the genomic DNA was 32.1 mol%. Based on 16S rRNA gene sequence analysis, this organism was most closely related to Caminibacter hydrogeniphilus (94.9% similarity). On the basis of phenotypic and phylogenetic data, it is proposed that the isolate represents a novel species, Caminibacter profundus sp. nov. The type strain is CRT (=DSM 15016T=JCM 11957T). The phylogenetic data also correlate well with the significant phenotypic differences between the lineage encompassing the genera Nautilia and Caminibacter and other members of the class 'Epsilonproteobacteria'. The lineage encompassing the genera Nautilia and Caminibacter is therefore proposed as a new order, Nautiliales ord. nov., represented by a single family, Nautiliaceae fam. nov.

Deferribacter abyssi sp. nov., an anaerobic thermophile from deep-sea hydrothermal vents of the Mid-Atlantic Ridge.

Two strains of thermophilic, anaerobic, chemolithoautotrophic bacteria, designated JR(T) and DR, were isolated from hydrothermal samples collected on the Mid-Atlantic Ridge from the Rainbow (36 degrees 16' N, 33 degrees 54' W) and Menez Gwen (37 degrees 50' N, 31 degrees 50' W) vent fields, respectively. Cells of both isolates were short, straight- to vibrio-shaped, motile rods with one polar flagellum, and were Gram-negative and non-sporulating. Strain JR(T) was characterized in detail. It was found to grow optimally at pH 6.5-6.7, at 60 degrees C and in the presence of 30 g NaCl l(-1). Strain JR(T) could use molecular hydrogen, acetate, succinate, pyruvate and proteinaceous compounds as electron donors, and elemental sulfur, nitrate or Fe(III) as electron acceptors. No fermentation of organic substrates occurred. The G+C content of the DNA of strain JR(T) was 30.8 mol%. Strain DR (=DSM 14927) possessed the same morphology and pH, temperature and salinity optima and ranges, and used the same electron acceptors as strain JR(T). On the basis of their 16S rDNA sequences (1517 nucleotides), strains JR(T) and DR were identical and distantly related to Deferribacter thermophilus and Deferribacter desulfuricans (95.3 and 95.2 % sequence similarity, respectively). Based on their phenotypic and phylogenetic characteristics, it is proposed that both strains are members of a new species of the genus Deferribacter, for which the name Deferribacter abyssi (type strain JR(T)=DSM 14873(T)=JCM 11955(T)) is proposed.

Vulcanithermus mediatlanticus gen. nov., sp. nov., a novel member of the family Thermaceae from a deep-sea hot vent.

A novel thermophilic, microaerophilic, facultatively chemolithoheterotrophic bacterium designated strain TR(T) was isolated from a sample of a deep-sea hydrothermal chimney collected at the Rainbow vent field on the Mid-Atlantic Ridge (36 degrees 14'N). Gram-negative, non-spore-forming, non-motile rods occurred singly or in pairs. The organism grew in the temperature range 37-80 degrees C with an optimum at 70 degrees C and at pH 5.5-8.4 with an optimum around 6.7. The NaCl range for growth was 10-50 g l(-1) with an optimum of 30 g l(-1). Strain TR(T) grew chemoorganoheterotrophically with carbohydrates, proteinaceous substrates, organic acids and alcohols using oxygen or nitrate as electron acceptors. The isolate was able to grow at oxygen concentrations from 0.5 to 21%. Oxygen concentrations that promoted fastest growth ranged from 4 to 8% under agitation. The novel isolate was able to grow lithoheterotrophically with molecular hydrogen as the energy source. The G + C content of the genomic DNA was 68.4 mol%. Phylogenetic analysis of the 16S rDNA sequence placed strain TR(T) within the phylum Deinococcus-Thermus of the Bacteria. On the basis of phenotypic and phylogenetic data, it is proposed that this isolate should be described as a member of a novel species of a new genus as Vulcanithermus mediatlanticus gen. nov., sp. nov. The type strain is TR(T) (= DSM 14978T = VKM B-2292T = JCM 11956T).

Oceanithermus profundus gen. nov., sp. nov., a thermophilic, microaerophilic, facultatively chemolithoheterotrophic bacterium from a deep-sea hydrothermal vent.

A novel moderately thermophilic, organotrophic, microaerophilic, facultatively chemolithotrophic bacterium, designated strain 506(T), was isolated from a deep-sea hydrothermal vent site at 13 degrees N in the East Pacific Rise. Cells were Gram-negative, non-motile rods. The organism grew in the temperature range 40-68 degrees C, with an optimum at 60 degrees C, and in the pH range 5.5-8.4, with an optimum around pH 7.5. The NaCl concentration for growth was in the range 10-50 g l(-1), with an optimum at 30 g l(-1). Strain 506(T) grew chemoorganoheterotrophically with carbohydrates, proteinaceous substrates, organic acids and alcohols using oxygen or nitrate as electron acceptor. Alternatively, strain 506(T) was able to grow lithoheterotrophically with molecular hydrogen as the energy source. The G +C content of the genomic DNA was 62.9 mol%. Phylogenetic analysis of the 16S rDNA sequence placed strain 506(T) in the family Thermaceae. On the basis of phenotypic and phylogenetic data, strain 506(T) (= DSM 14977(T) = VKM B-2274(T)) is proposed as the type strain of a novel species in a new genus, Oceanithermus profundus gen. nov., sp. nov.

Isolation and characterization of a novel As(V)-reducing bacterium: implications for arsenic mobilization and the genus Desulfitobacterium.

Dissimilatory arsenate-reducing bacteria have been implicated in the mobilization of arsenic from arsenic-enriched sediments. An As(V)-reducing bacterium, designated strain GBFH, was isolated from arsenic-contaminated sediments of Lake Coeur d'Alene, Idaho. Strain GBFH couples the oxidation of formate to the reduction of As(V) when formate is supplied as the sole carbon source and electron donor. Additionally, strain GBFH is capable of reducing As(V), Fe(III), Se(VI), Mn(IV) and a variety of oxidized sulfur species. 16S ribosomal DNA sequence comparisons reveal that strain GBFH is closely related to Desulfitobacterium hafniense DCB-2(T) and Desulfitobacterium frappieri PCP-1(T). Comparative physiology demonstrates that D. hafniense and D. frappieri, known for reductively dechlorinating chlorophenols, are also capable of toxic metal or metalloid respiration. DNA-DNA hybridization and comparative physiological studies suggest that D. hafniense, D. frappieri, and strain GBFH should be united into one species. The isolation of an Fe(III)- and As(V)-reducing bacterium from Lake Coeur d'Alene suggests a mechanism for arsenic mobilization in these contaminated sediments while the discovery of metal or metalloid respiration in the genus Desulfitobacterium has implications for environments cocontaminated with arsenious and chlorophenolic compounds.

Limnobacter thiooxidans gen. nov., sp. nov., a novel thiosulfate-oxidizing bacterium isolated from freshwater lake sediment.

Two novel thiosulfate-oxidizing strains were isolated from sediment of the littoral zone of a freshwater lake (Lake Chiemsee, Bavaria, Germany). The new isolates, designated CS-K1 and CS-K2T, were gram-negative, slightly curved rods with pointed ends that were motile by means of single polar flagella. Both strains were obligately aerobic and grew on a variety of organic substrates, but not autotrophically. The utilization of thiosulfate led to an increase in the growth yield, indicating that these strains were able to grow chemolithoheterotrophically by oxidation of thiosulfate to sulfate. The optimum thiosulfate concentrations for growth were determined to be 10 mM for strain CS-K1 and 20 mM for strain CS-K2T. Phylogenetically, both strains were affiliated to the beta-Proteobacteria. Their characterization by a polyphasic approach resulted in the placement of both strains into a single species that is related only distantly to any known type species. Thus, the creation of a novel taxon is proposed, with the name Limnobacter thiooxidans gen. nov., sp. nov., to include the novel strains. In addition, the phylogenetic position of the chemolithoheterotrophic strain 'Thiobacillus' Q was determined.