Use of Nitrogen-15-Enriched Escherichia coli as a Bacterial Tracer in Karst Aquifers.

Karst aquifers are susceptible to contamination by microorganisms, but relatively few studies have used bacteria as tracers. We demonstrate the utility of Escherichia coli enriched in the stable isotope nitrogen-15 (15 N) as a novel bacterial tracer. Nonpathogenic E. coli from two springs in central Kentucky were grown on 15 N-enriched media. Survival of E. coli and persistence of the isotopic signal were assessed in two sets of laboratory experiments conducted with sterilized spring water in dark microcosms at 14 °C. First, isotopically labeled bacteria survived for 130 d at concentrations within one log unit of the average initial value, and there was no significant difference in δ15 N values from Day 1 to Day 130. Second, water samples with E. coli were inoculated with either of two different species of protozoa (Tetrahymena pyriformis or Colpoda steinii). During 7 d, δ15 N values increased in T. pyriformis while bacterial populations decreased. In a field test, following a 2.1-cm rainfall, 15 N-labeled E. coli, solutes (rhodamine WT dye and bromide), and latex microspheres were injected into a sinkhole approximately 530 m upgradient of a spring. Breakthrough of all tracers coincided, but microspheres were remobilized by subsequent storms, unlike other tracers. Enriched E. coli exhibited more tailing than solute tracers during the initial storm-flow recession. These results indicate that 15 N-enriched E. coli is a viable tracer of bacterial transport in karst aquifers, although predation may attenuate the isotopic signal in systems that are not rapidly flushed.

Precipitation influences on uptake of a global pollutant by a coastal avian species.

Climatic variation, including precipitation amounts and timing, has been linked to abundance and breeding success of many avian species. Less studied, but also of significance, is the consequence of climatic variability on the exposure and uptake of nutrients and contaminants by wildlife. The authors examined mercury (Hg) concentrations in nestling wood stork feathers in a coastal setting over a 16-yr period to understand the influence of rainfall amounts on Hg transfer by parental provisioning relative to habitat use, assuming differential bioavailability of Hg within freshwater and saltwater habitat types. Coastal Hg uptake by stork nestlings was linked to freshwater habitat use, as indicated by stable carbon isotope (δ(13)C) analyses. Cumulative rainfall amounts exceeding 220 cm in the 23 mo preceding the breeding seasons resulted in greater use of freshwater wetlands as foraging habitat and greater Hg accumulation by nestling storks.

Effects of lead shot ingestion on bone mineralization in a population of red-legged partridge (Alectoris rufa).

The effect of lead (Pb) toxicity on bone mineralization was investigated in a wild population of red-legged partridge (Alectoris rufa) inhabiting a farmland area contaminated with Pb-shot from recreational hunting activities in Albacete, a southeastern province of Spain. Femora from 40 specimens of red-legged partridge were analyzed for Pb by graphite furnace atomic absorption spectroscopy (GF-AAS), and for bone composition by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The FTIR and DRX data of bone were analyzed in detail to determine possible alterations in bone mineral chemistry and crystallinity due to Pb toxicity. Results showed a marked decrease in the degree of mineralization as Pb concentrations in bone tissue increased while XRD analyses showed that the crystallinity of apatite crystals increased with the Pb load in bone. These load-dependent effects are indicative that Pb contamination altered bone remodeling by reducing new bone mineral formation and demonstrate that bone quality is a sensitive indicator of adverse effects on wild bird populations exposed to Pb pollution.

Mercury concentrations in nestling wading birds relative to diet in the southeastern United States: a stable isotope analysis.

Mercury (Hg) is a ubiquitous environmental contaminant that is transferred trophically through aquatic and terrestrial food webs. To better understand the routes of Hg uptake in organisms that rely on both aquatic and terrestrial food resources, we analyzed feather and down samples from nestling wading birds of varying trophic positions in both inland and coastal colonies. We used stable nitrogen and carbon isotope analyses to evaluate trophic positions of individual species (δ(15)N) and differences in foraging habitat use (δ(13)C). Inland, aquatic species had higher trophic status than the single terrestrial species examined, and the expected positive relationship between δ(15)N and Hg content of feathers was observed. However, the same was not true for all species from coastal colonies. Feathers from species that primarily consumed saltwater prey were relatively high in δ(15)N value and low in Hg content, which is opposite of the trend expected due to Hg biomagnification in food chains. In contrast, coastal species foraging in freshwater or a combination of freshwater and saltwater habitats displayed greater Hg contents in feathers. The apparent differential use of the two aquatic systems (freshwater and saltwater) in coastal environments by wading bird species results in variations in δ(15)N values and Hg contents in nestling feathers not found in species associated with only freshwater systems.

Comparative geochemical and microbiological characterization of two thermal pools in the Uzon Caldera, Kamchatka, Russia.

Arkashin Schurf (Arkashin) and Zavarzin Spring (Zavarzin), two active thermal pools in the Uzon Caldera, Kamchatka, Russia, were studied for geochemical and microbiological characterization. Arkashin, the smaller of the two pools, had broader temperature and pH ranges, and the sediments had higher concentrations of total As (4,250 mg/kg) relative to Zavarzin (48.9 mg/kg). Glycerol dialkyl glycerol tetraether profiles represented distinct archaeal communities in each pool and agreed well with previous studies of these pools. Although no archaeal 16S rRNA sequences were recovered from Arkashin, sequences recovered from Zavarzin were mostly representatives of the Crenarchaeota and "Korarchaeota," and 13% of the sequences were unclassifiable. The bacterial community in Arkashin was dominated by uncultured "Bacteroidetes," Hydrogenobaculum of the Aquificales and Variovorax of the Betaproteobacteria, and 19% of the sequences remained unclassified. These results were consistent with other studies of As-rich features. The most abundant members of the Zavarzin bacterial community included the Chloroflexi, as well as members of the classes Deltaproteobacteria and Clostridia. In addition, 24% of the sequences were unclassified and at least 5% of those represent new groups among the established Bacterial phyla. Ecological structure in each pool was inferred from taxonomic classifications and bulk stable isotope δ values of C, N, and S. Hydrogenobaculum was responsible for primary production in Arkashin. However, in Zavarzin, the carbon source appeared to be allochthonous to the identified bacterial community members. Additionally, sequences related to organisms expected to participate in N and S cycles were identified from both pools.

Mercury contamination in turtles and implications for human health.

Mercury contamination threatens many ecosystems worldwide. Methylmercury bioaccumulates at each trophic level, and biomagnifies within individuals over time. Long-lived turtles often occupy high trophic positions and are likely to accumulate mercury in contaminated habitats. Millions of turtles worldwide are sold in Asia for human consumption, and consumers may be at risk if turtles contain high levels of mercury. The authors dissected 71 turtles from 14 food trade species and analyzed their tissues (liver, kidneys, muscle, claws, and scutes) for total mercury content. Mercury was generally highest in carnivores, and lowest in herbivores. Liver and scutes had the highest concentrations. The authors compared mercury concentrations with consumption limits developed by the U.S. Environmental Protection Agency and Food and Drug Administration to evaluate mercury in fish tissue. Several samples exceeded the recommended 1,900 parts per billion (ppb) consumption threshold, indicating that consumers who eat certain turtle species frequently may be at risk for mercury-related health problems.

Mesoscale patterns of altitudinal tenancy in migratory wood warblers inferred from stable carbon isotopes.

We analyzed carbon isotope ratios (delta13C) of liver and pectoral muscle of Black-throated Blue Warblers (Dendroica caerulescens) to provide a mesoscale perspective on altitudinal tenancy in the Appalachian Mountains, North Carolina, U.S.A. Movements of males are poorly understood, particularly the degree to which yearlings (first breeding season) and older males (second or later breeding season) wander altitudinally during the breeding season. Liver and muscle delta13C values of warblers exhibited significant year and altitude effects, but yearling and older males were isotopically indistinguishable. Liver delta13C values increased with altitude at the rate of approximately 0.5% per hundred per 1000 m. The altitudinal lapse rate of muscle delta13C (approximately l1.1% per hundred per 1000 m) was nearly identical to the average rate of increase reported in several groups of C3 plants (approximately 1.1% per hundred per 1000 m). This suggests that the majority of males foraged within relatively narrow altitudinal zones during the breeding season. We caution, however, that the discrimination of altitudinal trends in carbon isotope ratios depends on relatively large multiyear samples. Given the scatter in data, it is unlikely that individuals can be accurately assigned to a particular altitude from carbon isotope values. Rapid adjustment of liver and muscle delta13C values to local altitudinal environments is consistent with the results of experimental dietary studies that show carbon turnover rates are relatively rapid in small migratory passerines. In a broader context, carbon isotope data have been increasingly used as proxies for wintering habitat use of Nearctic-Neotropical migratory passerines. However, tissues with high metabolic rates are unlikely to retain much isotopic signal of wintering habitat use by the time migrants reach their breeding territories.

Desulfosporosinus youngiae sp. nov., a spore-forming, sulfate-reducing bacterium isolated from a constructed wetland treating acid mine drainage.

Strain JW/YJL-B18(T), a spore-forming, sulfate-reducing bacterium, was isolated from constructed wetland sediment. Cells were curved rods, 0.7-1.2 mum in diameter and 3-7 mum long. Despite being phylogenetically a member of the Gram-type-positive phylum Firmicutes, cells stained Gram-negative at all growth phases. Strain JW/YJL-B18(T) grew at 8-39 degrees C, with an optimum at 32-35 degrees C and no growth at 4 degrees C or below or at 42 degrees C or above. The pH(25 degrees C) range for growth was 5.7-8.2, with an optimum at pH(25 degrees C) 7.0-7.3, and no growth was detected at or below pH 5.2 or at or above pH 8.4. The salinity range for growth was 0-3 % (NaCl/KCl 9 : 1). Strain JW/YJL-B18(T) utilized as carbon and energy sources beef extract, yeast extract, formate, succinate, lactate, pyruvate, ethanol and toluene. Fumarate, sulfate, sulfite and thiosulfate were reduced in the presence of lactate. Arsenate (V) was not used as an electron acceptor. Strain JW/YJL-B18(T) showed no indication of growth under autotrophic conditions. The predominant cellular fatty acids were C(16 : 1) and C(16 : 0). The genomic DNA G+C content was 36.6 mol% (HPLC). 16S rRNA gene sequence analysis indicated that strain JW/YJL-B18(T) fell into the genus Desulfosporosinus, with Desulfosporosinus auripigmenti OREX-4(T) as its closest neighbour with a validly published name (97.9 % similarity). Based on molecular genetic evidence and physiological and biochemical characters including differences in the DNA G+C content, we propose to place strain JW/YJL-B18(T) (=DSM 17734(T) =ATCC BAA-1261(T)) as the type strain of a novel species, Desulfosporosinus youngiae sp. nov.

Caldanaerovirga acetigignens gen. nov., sp. nov., an anaerobic xylanolytic, alkalithermophilic bacterium isolated from Trego Hot Spring, Nevada, USA.

An anaerobic thermophilic bacterium, designated strain JW/SA-NV4(T), was isolated from a xylan-supplemented enrichment culture from Trego hot spring located within the Black Rock Desert (NV, USA). Cells were generally straight or slightly bent rod-shaped, 0.4-0.8 microm in width and 3-6 microm in length during exponential growth. Cells from stationary phase were variable in size and shape, showing curved or bent morphology. Motility was not seen and flagella were not observed in electron micrographs. Sporulation was not observed. Strain JW/SA-NV4(T) stained Gram-negative but is phylogenetically Gram-type positive. Growth occurred at pH(25 degrees C) 6.8-8.8, with optimum growth at pH 8.4; no growth occurred at pH 9.0 or above or at 6.5 or below. With glucose or xylose as the carbon source, strain JW/SA-NV4(T) grew at 44-74 degrees C; no growth occurred at 76 degrees C or above or at 42 degrees C or below. However, the optimum temperature was 62 and 66 degrees C when grown on glucose and xylose, respectively. The shortest doubling time observed with glucose was approximately 4 h, and with xylose approximately 3.4 h. Strain JW/SA-NV4(T) tolerated an atmosphere containing up to 0.1 % O(2); no growth occurred at a gas atmosphere of 0.2 % O(2). Chemo-organotrophic growth occurred with xylose, glucose, mannose, xylan, pyruvate, fructose, ribose, Casamino acids, mannitol, tryptone, peptone, cellobiose and yeast extract. When grown in mineral media containing 1 g yeast extract l(-1) as an electron donor, thiosulfate and sulfur were reduced to sulfide. The G+C content of the DNA was 38.6 mol% (HPLC). 16S rRNA gene sequence analysis placed strain JW/SA-NV4(T) within the order Thermoanaerobacterales and within the Thermoanaerobacterales Incertae Sedis Family III, specifically between taxa classified within the genera Thermosediminibacter and Thermovenabulum. The closest phylogenetic neighbours were Thermosediminibacter oceani JW/IW-1228P(T) (94.2 % 16S rRNA gene sequence similarity) and Thermosediminibacter litoriperuensis JW/YJL-1230-7/2(T) (94.0 %) [Lee, Y.-J., Wagner, I. D., Brice, M. E., Kevbrin, V. V., Mills, G. L., Romanek, C. S. & Wiegel, J. (2005). Extremophiles 9, 375-383]. Based on physiological and genotypic characteristics, strain JW/SA-NV4(T) (=DSM 18802(T)=ATCC BAA-1454(T)) is proposed to represent the type strain of a novel species in a novel genus, Caldanaerovirga acetigignens gen. nov., sp. nov.

Thermoanaerobacter uzonensis sp. nov., an anaerobic thermophilic bacterium isolated from a hot spring within the Uzon Caldera, Kamchatka, Far East Russia.

Several strains of heterotrophic, anaerobic thermophilic bacteria were isolated from hot springs of the Uzon Caldera, Kamchatka, Far East Russia. Strain JW/IW010(T) was isolated from a hot spring within the West sector of the Eastern Thermal field, near Pulsating Spring in the Winding Creek area. Cells of strain JW/IW010(T) were straight to slightly curved rods, 0.5 mum in width and variable in length from 2 to 5 mum and occasionally up to 15 mum, and formed oval subterminal spores. Cells stained Gram-negative, but were Gram-type positive. Growth was observed between 32.5 and 69 degrees C with an optimum around 61 degrees C (no growth occurred at or below 30 degrees C, or at or above 72 degrees C). The pH(60 degrees C) range for growth was 4.2-8.9 with an optimum at 7.1 (no growth occurred at or below pH(60 degrees C) 3.9, or at 9.2 or above). The shortest observed doubling-time at pH(60 degrees C) 6.9 and 61 degrees C was 30 min. Strain JW/IW010(T) was chemo-organotrophic; yeast extract, peptone, Casamino acids and tryptone supported growth. Yeast extract was necessary for the utilization of non-proteinaceous substrates, and growth was observed with inulin, cellobiose, maltose, sucrose, glucose, fructose, galactose, mannose, xylose, trehalose, mannitol, pyruvate and crotonate. The G+C content of the genomic DNA of strain JW/IW010(T) was 33.6 mol% (HPLC method). The major phospholipid fatty acids were iso-15 : 0 (53.5 %), 15 : 0 (11.8 %), 16 : 0 (7.3 %), 10-methyl 16 : 0 (7.3 %) and anteiso-15 : 0 (5.3 %). 16S rRNA gene sequence analysis placed strain JW/IW010(T) in the genus Thermoanaerobacter of the family 'Thermoanaerobacteriaceae' (Firmicutes), with Thermoanaerobacter sulfurigignens JW/SL-NZ826(T) (97 % 16S rRNA gene sequence similarity) and Thermoanaerobacter kivui DSM 2030(T) (94.5 %) as the closest phylogenetic relatives with validly published names. The level of DNA-DNA relatedness between strain JW/IW010(T) and Thermoanaerobacter sulfurigignens JW/SL-NZ826(T) was 64 %. Based on the physiological, phylogenetic and genotypic data, strain JW/IW010(T) represents a novel taxon, for which the name Thermoanaerobacter uzonensis sp. nov. is proposed. The type strain is JW/IW010(T) (=ATCC BAA-1464(T)=DSM 18761(T)). The effectively published strain, 1501/60, of 'Clostridium uzonii' [Krivenko, V. V., Vadachloriya, R. M., Chermykh, N. A., Mityushina, L. L. & Krasilnikova, E. N. (1990). Microbiology (English translation of Mikrobiologiia) 59, 741-748] had approximately 88.0 % DNA-DNA relatedness with strain JW/IW010(T) and was included in the novel taxon.

Global occurrence of archaeal amoA genes in terrestrial hot springs.

Despite the ubiquity of ammonium in geothermal environments and the thermodynamic favorability of aerobic ammonia oxidation, thermophilic ammonia-oxidizing microorganisms belonging to the crenarchaeota kingdom have only recently been described. In this study, we analyzed microbial mats and surface sediments from 21 hot spring samples (pH 3.4 to 9.0; temperature, 41 to 86 degrees C) from the United States, China, and Russia and obtained 846 putative archaeal ammonia monooxygenase large-subunit (amoA) gene and transcript sequences, representing a total of 41 amoA operational taxonomic units (OTUs) at 2% identity. The amoA gene sequences were highly diverse, yet they clustered within two major clades of archaeal amoA sequences known from water columns, sediments, and soils: clusters A and B. Eighty-four percent (711/846) of the sequences belonged to cluster A, which is typically found in water columns and sediments, whereas 16% (135/846) belonged to cluster B, which is typically found in soils and sediments. Although a few amoA OTUs were present in several geothermal regions, most were specific to a single region. In addition, cluster A amoA genes formed geographic groups, while cluster B sequences did not group geographically. With the exception of only one hot spring, principal-component analysis and UPGMA (unweighted-pair group method using average linkages) based on the UniFrac metric derived from cluster A grouped the springs by location, regardless of temperature or bulk water pH, suggesting that geography may play a role in structuring communities of putative ammonia-oxidizing archaea (AOA). The amoA genes were distinct from those of low-temperature environments; in particular, pair-wise comparisons between hot spring amoA genes and those from sympatric soils showed less than 85% sequence identity, underscoring the distinctness of hot spring archaeal communities from those of the surrounding soil system. Reverse transcription-PCR showed that amoA genes were transcribed in situ in one spring and the transcripts were closely related to the amoA genes amplified from the same spring. Our study demonstrates the global occurrence of putative archaeal amoA genes in a wide variety of terrestrial hot springs and suggests that geography may play an important role in selecting different assemblages of AOA.

Description of Caldalkalibacillus uzonensis sp. nov. and emended description of the genus Caldalkalibacillus.

Strain JW/WZ-YB58T, a thermophilic (42-64 degrees C), aerobic, alkalitolerant (pH25 degrees C 6.4-9.7), heterotrophic, sporulating, retarded-peritrichously flagellated and slightly curved rod-shaped bacterium, was isolated from the hot spring Zarvarzin II in the East Thermal Field of the Uzon Caldera, Kamchatka (Far East Russia). The isolate tolerated high concentrations of CO. The major membrane phospholipid fatty acids of JW/WZ-YB58T included iso-C15 : 0 (24.5 %), anteiso-C15 : 0 (18.3 %) and iso-C17 : 0 (17.5 %). The G+C content of the genomic DNA is 45 mol% (HPLC method). Based on 16S rRNA gene sequence analysis and physiological properties, isolate JW/WZ-YB58T (=ATCC BAA-1258T =DSM 17740T) is proposed as the type strain of Caldalkalibacillus uzonensis sp. nov. In contrast to the type species Caldalkalibacillus thermarum, a catalase-reaction-positive aerobe, C. uzonensis was catalase-reaction-negative; thus the description of the genus Caldalkalibacillus is emended to include a catalase-reaction-negative species.

Factors controlling the distribution of archaeal tetraethers in terrestrial hot springs.

Glycerol dialkyl glycerol tetraethers (GDGTs) found in hot springs reflect the abundance and community structure of Archaea in these extreme environments. The relationships between GDGTs, archaeal communities, and physical or geochemical variables are underexamined to date and when reported often result in conflicting interpretations. Here, we examined profiles of GDGTs from pure cultures of Crenarchaeota and from terrestrial geothermal springs representing a wide distribution of locations, including Yellowstone National Park (United States), the Great Basin of Nevada and California (United States), Kamchatka (Russia), Tengchong thermal field (China), and Thailand. These samples had temperatures of 36.5 to 87 degrees C and pH values of 3.0 to 9.2. GDGT abundances also were determined for three soil samples adjacent to some of the hot springs. Principal component analysis identified four factors that accounted for most of the variance among nine individual GDGTs, temperature, and pH. Significant correlations were observed between pH and the GDGTs crenarchaeol and GDGT-4 (four cyclopentane rings, m/z 1,294); pH correlated positively with crenarchaeol and inversely with GDGT-4. Weaker correlations were observed between temperature and the four factors. Three of the four GDGTs used in the marine TEX(86) paleotemperature index (GDGT-1 to -3, but not crenarchaeol isomer) were associated with a single factor. No correlation was observed for GDGT-0 (acyclic caldarchaeol): it is effectively its own variable. The biosynthetic mechanisms and exact archaeal community structures leading to these relationships remain unknown. However, the data in general show promise for the continued development of GDGT lipid-based physiochemical proxies for archaeal evolution and for paleo-ecology or paleoclimate studies.

Influence of feeding ecology on blood mercury concentrations in four species of turtles.

Mercury is a relatively well-studied pollutant because of its global distribution, toxicity, and ability to bioaccumulate and biomagnify in food webs: however, little is known about bioaccumulation and toxicity of Hg in turtles. Total Hg (THg) concentrations in blood were determined for 552 turtles representing four different species (Chelydra serpentina, Sternotherus odoratus, Chrysemys picta, and Pseudemys rubriventris) from a Hg-contaminated site on the South River (VA, USA) and upstream reference sites. Methylmercury and Se concentrations also were determined in a subset of samples. Because the feeding ecology of these species differs drastically, stable isotopes of carbon (delta13C) and nitrogen (delta15N) were employed to infer the relationship between relative trophic position and Hg concentrations. Significant differences were found among sites and species, suggesting that blood can be used as a bioindicator of Hg exposure in turtles. We found differences in THg concentrations in turtles from the contaminated site that were consistent with their known feeding ecology: C. serpentina > or = S. odoratus > C. picta > P. rubriventris. This trend was generally supported by the isotope data, which suggested that individual turtles were feeding at more than one trophic level. Methylmercury followed similar spatial patterns as THg and was the predominant Hg species in blood for all turtles. Blood Se concentrations were low in the system, but a marginally positive relationship was found between THg and Se when species were pooled. The blood THg concentrations for the turtles in the present study are some of the highest reported in reptiles, necessitating further studies to investigate potential adverse effects of these high concentrations.

Bioaccumulation of trace elements in omnivorous amphibian larvae: implications for amphibian health and contaminant transport.

Despite the influence that amphibians have on the flow of energy and nutrients in ecological systems, the role that amphibians play in transporting contaminants through food webs has received very little attention. This study was undertaken to investigate bioaccumulation of trace elements in amphibians relative to other small aquatic organisms in a contaminated wetland. We collected bullfrog larvae (Rana catesbeiana) along with three other species of small vertebrates and four species of invertebrates from a site contaminated with a wide array of trace elements and analyzed them for trace element concentrations and stable nitrogen and carbon isotope composition. We found that amphibian larvae accumulated the highest concentrations of most trace elements, possibly due to their feeding ecology. These results suggest that omnivorous amphibian larvae can serve as a critical link for trace element trophic transfer. Their propensity to accumulate trace elements may have important implications for amphibian health in contaminated environments and should be further investigated.

Clostridium aciditolerans sp. nov., an acid-tolerant spore-forming anaerobic bacterium from constructed wetland sediment.

An obligately anaerobic, spore-forming, moderately acid-tolerant bacterium, strain JW/YJL-B3T, was isolated from a sediment sample from a constructed wetland system receiving acid sulfate water. Based on 16S rRNA gene sequence analysis, the isolate belonged to the Firmicutes branch with Clostridium drakei SL1T (96.2 % gene sequence similarity) as its closest relative. The G+C content of the genomic DNA was 30.8 mol% (HPLC). Cells were straight to curved rods, 0.5-1.0 microm in diameter and 3.0-9.0 microm in length. The temperature range for growth was 20-45 degrees C, with an optimum around 35 degrees C. Growth was not detected below 18 degrees C or above 47 degrees C. The pH range for growth was broad, pH(25 degrees C) 3.8-8.9, with an optimum at 7.0-7.5. However at pH 4.5, the strain grew at 52 % of the optimal growth rate. The salinity range was 0-1.5 % NaCl (w/v). Strain JW/YJL-B3T utilized beef extract, Casamino acids, peptone, tryptone, arabinose, cellobiose, fructose, galactose, glucose, lactose, maltose, mannose, raffinose, ribose, sucrose, xylose, pyruvate, glutamate and inulin as a carbon and energy source. There were no indications of growth under aerobic or autotrophic conditions. The isolate produced acetate, butyrate and ethanol as fermentation end products from glucose. Based on these characteristics and other physiological properties, the isolate is placed into the novel taxon, Clostridium aciditolerans sp. nov., with strain JW/YJL-B3T (=DSM 17425T=ATCC BAA-1220T) as the type strain.

Effect of in ovo exposure to PCBs and Hg on Clapper Rail bone mineral chemistry from a contaminated salt marsh in coastal Georgia.

The effect of Hg and PCBs (Aroclor 1268) on bone characteristics was investigated in a population of Clapper Rails (Rallus longirostris) inhabiting contaminated and unimpacted estuarine marsh systems in coastal Georgia. Exposure to contaminants did not affect the length or weight of leg bones, but it significantly altered the chemical composition of the bone. Specifically, bone in the contaminated site had a higher Ca to P, and lower carbonate and acid phosphate content. These characteristics are typical of more mature bone mineral and indicate that toxicants have accelerated bone maturation. FTIR spectroscopy data revealed a dose dependent change in the crystallinity of bone mineral, and the relative proportion of specific PO4 groups in different molecular environments in the bone, with toxicants loads. These changes are most probably related to a hormonal alteration of the rate of bone remodelation induced by exposure to toxicant loads.

Gracilibacter thermotolerans gen. nov., sp. nov., an anaerobic, thermotolerant bacterium from a constructed wetland receiving acid sulfate water.

An obligatorily anaerobic, thermotolerant, asporogenic bacterium, strain JW/YJL-S1(T), was isolated from a sediment sample of a constructed wetland system receiving acid sulfate water (pH 1.6-3.0). Cells of strain JW/YJL-S1(T) were straight to curved rods 0.2-0.4 mum in diameter and 2.0-7.0 mum in length, and stained Gram-negative. Growth of strain JW/YJL-S1(T) was observed at 25-54 degrees C (no growth at or below 20 or at or above 58 degrees C), with an optimum temperature range for growth of 42.5-46.5 degrees C. The pH(25 degrees C) range for growth was 6.0-8.25 (no growth at or below pH 5.7 or at or above pH 8.5), with optimum growth at pH 6.8-7.75. The salinity range for growth was 0-1.5 % (w/v) NaCl, with an optimum at 0-0.5 %. During growth on glucose the isolate produced acetate, lactate and ethanol as main fermentation end products. The fatty acid composition was dominated by branched-chain compounds: i15 : 0, a15 : 0, i16 : 0 and i17 : 0. The G+C content of the genomic DNA was 42.8 mol% (HPLC). Strain JW/YJL-S1(T) showed polymorphism of the 16S rRNA gene. Its closest relative was the thermophilic Clostridium thermosuccinogenes DSM 5807(T) (a member of Clostridium cluster III) (a blastn search revealed Clostridium pascui DSM 10365(T) to have 92.7 % gene sequence similarity, the highest value). The inferred phylogenetic trees placed strain JW/YJL-S1(T) between Clostridium clusters I/II and III. Based on the morphological and phylogenetic data presented, JW/YJL-S1(T) (=DSM 17427(T)=ATCC BAA-1219(T)) is proposed as the type strain of a novel species in a new genus, Gracilibacter thermotolerans gen. nov., sp. nov.

Isolation and partial characterization of proteins involved in maternal transfer of selenium in the western fence lizard (Sceloporus occidentalis).

Selenium from dietary exposure is efficiently transferred from mother to offspring in oviparous vertebrates, where it can cause severe teratogenic effects. We isolated and partially characterized proteins involved in maternal transfer of selenium in the oviparous lizard Sceloporus occidentalis using size-exclusion chromatography, inductively coupled plasma-mass spectrometry, and polyacrylamide gel electrophoresis. Selenium from dietary selenomethionine exposure was incorporated into at least three egg proteins. One of these proteins was lipovitellin. The other two proteins may be part of a previously unknown mechanism of maternal transfer of Se that is independent of vitellogenesis or albumin secretion. Our results suggest at least three pathways for maternal transfer of Se in vertebrates that may vary in importance depending on the species.

Thermalkalibacillus uzonensis gen. nov. sp. nov, a novel aerobic alkali-tolerant thermophilic bacterium isolated from a hot spring in Uzon Caldera, Kamchatka.

A novel thermophilic, alkali-tolerant, and CO-tolerant strain JW/WZ-YB58(T) was isolated from green mat samples obtained from the Zarvarzin II hot spring in the Uzon Caldera, Kamchatka (Far East Russia). Cells were Gram-type and Gram stain-positive, strictly aerobic, 0.7-0.8 mum in width and 5.5-12 mum in length and produced terminal spherical spores of 1.2-1.6 mum in diameter with the mother cell swelling around 2 mum in diameter (drumstick-type morphology). Cells grew optimally at pH(25 degrees C) 8.2-8.4 and temperature 50-52 degrees C and tolerated maximally 6% (w/v) NaCl. They were strict heterotrophs and could not use either CO or CO(2 )(both with or without H(2)) as sole carbon source, but tolerated up to 90% (v/v) CO in the headspace. The isolate grew on various complex substrates such as yeast extract, on carbohydrates, and organic acids, which included starch, D: -galactose, D: -mannose, glutamate, fumarate and acetate. Catalase reaction was negative. The membrane polar lipids were dominated by branched saturated fatty acids, which included iso-15:0 (24.5%), anteiso-15:0 (18.3%), iso-16:0 (9.9%), iso-17:0 (17.5%) and anteiso-17:0 (9.7%) as major constituents. The DNA G+C content of the strain is 45 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain JW/WZ-YB58(T) is distantly (<93% similarity) related to members of Bacillaceae. On the basis of 16S rRNA gene sequence, physiological and phenotypic characteristics, the isolate JW/WZ-YB58(T) (ATCC BAA-1258; DSM 17740) is proposed to be the type strain for the type species of the new taxa within the family Bacillaceae, Thermalkalibacillus uzoniensis gen. nov. sp. nov. The Genbank accession number for the 16S rRNA gene sequence is DQ221694.