Toxicity effects of four typical nanomaterials on the growth of <Emphasis Type="Italic">Escherichia coli</Emphasis>, <Emphasis Type="Italic">Bacillus subtilis</Emphasis> and <Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis>

To offer an insight into the toxicity of nanomaterials (NM) on the growth of bacteria, Escherichia coli (E. coli), Bacillus subtilis (B. subtilis) and Agrobacterium tumefaciens (A. tumefaciens) were exposed to nano-Au, nano-Ag, nano-Fe and fullerene (C₆₀) in this study. As an effective bactericide, nano-Ag induced high toxicity on these three bacteria; C₆₀ could inhibit their growth; however, B. subtilis and E. coli could recover as exposure time extended. Nano-Au and nano-Fe had hardly any effect on three bacteria. A. tumefaciens showed the lowest resistance and slowest growth rate during exposure. Images obtained by scanning electron microscope (SEM) revealed that nano-Ag could cause damage to the cell structure of three bacteria at 1 μg/mL. Slight damage on E. coli was found when exposed to C₆₀, whereas no obvious physical damage was found after exposure to nano-Au or nano-Fe. It is assumed that surface activities of NM might be responsible for the different toxic effects on these bacteria.     

New thermoelastic parameters of natural <Emphasis Type="Italic">C</Emphasis>2/<Emphasis Type="Italic">c</Emphasis> omphacite

The compressibility at room temperature and the thermal expansion at room pressure of two disordered crystals (space group C2/c) obtained by annealing a natural omphacite sample (space group P2/n) of composition close to Jd₅₆Di₄₄ and Jd₅₅Di₄₅, respectively, have been studied by single-crystal X-ray diffraction. Using a Birch–Murnaghan equation of state truncated at the third order [BM3-EoS], we have obtained the following coefficients: V ₀ = 421.04(7) Å³, K _T0 = 119(2) GPa, K′ = 5.7(6). A parameterized form of the BM3 EoS was used to determine the axial moduli of a, b and c. The anisotropy scheme is β _c  ≤ β _a  ≤ β _b , with an anisotropy ratio 1.05:1.00:1.07. A fitting of the lattice variation as a function of temperature, allowing for linear dependency of the thermal expansion coefficient on the temperature, yielded α_V(1bar,303K) = 2.64(2) × 10⁻⁵ K⁻¹ and an axial thermal expansion anisotropy of α _b  ≫ α _a  > α _c . Comparison of our results with available data on compressibility and thermal expansion shows that while a reasonable ideal behaviour can be proposed for the compressibility of clinopyroxenes in the jadeite–diopside binary join [K _T0 as a function of Jd molar %: K _T0 = 106(1) GPa + 0.28(2) × Jd_(mol%)], the available data have not sufficient quality to extract the behaviour of thermal expansion for the same binary join in terms of composition.     

Land-use-mediated <Emphasis Type="Italic">Escherichia coli</Emphasis> concentrations in a contemporary Appalachian watershed

A high-spatial resolution study design was used to investigate the relationship between land use practices, stream physicochemistry, hydroclimate, and stream Escherichia (E) coli concentrations in a mixed-land-use watershed in the Appalachian region. Stream samples were collected daily from six monitoring sites and analyzed for total E. coli counts using an enzyme metabolism indicator method. Statistical comparison of E. coli concentration time series showed significant (p?<?0.05) differences between study sites. Although highest average E. coli concentrations were observed at two agricultural sites (534 and 582 colony-forming counts (CFU) per 100 mL, respectively), highest total loadings were observed within the receiving stream, with values increasing downstream (2?×?10¹² and 4.2?×?10¹² study total CFU for bracketed upstream and downstream sites, respectively). No single physical variable displayed a significant correlation (p?<?0.05) with observed E. coli concentration at every site. However, sites displayed different patterns of significant correlations (p?<?0.05) between E. coli concentration and both physicochemical (e.g. pH, dissolved oxygen saturation) and hydroclimate variables (e.g. streamflow and precipitation). Percent agricultural land cover was the only land use category that showed significant (p?<?0.04) correlation with study average E. coli concentrations, thereby emphasizing the importance of land use practices to stream pathogen regimes. Results validate the analytical method and provide high-resolution, detailed, quantitative characterizations of stream E. coli regimes, thereby supplying land and water resource managers with science-based information to advance management decisions and improve public health.     

<Emphasis Type="Italic">BV I</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> photometry of RR Lyrae stars

We have obtained 26 372 CCD frames in the B, V, and I _c filters for 81 RR Lyrae stars in 2008–2010, using the 76-cm telescope of the South African Astronomical Observatory and the 40-cm telescope of the Cerro Armazones Observatory, North Catholic University (Chile) using an SBIG ST-10XME CCD camera. For 12 of these RR Lyrae stars, we also obtained 337 brightness measurements in the B and V bands in 2000–2001 using the 60-cm telescope of the High Altitude Mt. Maidanak Observatory (Republic of Uzbekistan). We present tables of observations, light curves, and improved light-curve elements for all these RR Lyrae stars. The Blazhko effect was detected for SU Hor.     

The Intertidal Burrowing Crab <Emphasis Type="Italic">Neohelice</Emphasis> (=<Emphasis Type="Italic">Chasmagnathus</Emphasis>) <Emphasis Type="Italic">granulata</Emphasis> Positively Affects Foraging of Rodents in South Western Atlantic Salt Marshes

The role of positive and indirect interactions is often crucial in communities with intense abiotic stress such as salt marshes. The burrowing crab, Neohelice (=Chasmagnathus) granulata, is the dominant benthic macroinvertebrate of southwest Atlantic marshes (southern Brazil to Northern Argentinean Patagonia), having strong direct and indirect effects on marsh soil and, in consequence, on marsh vegetation and primary consumers. In this work, we investigate if this crab indirectly modifies habitat use by the granivorous rodents, Akodon azarae and Oligoryzomys flavescens, by increasing nutrient availability and thus enhancing seed production by the marsh plant Spartina densiflora. The study was conducted at the Mar Chiquita Coastal Lagoon, Argentina (37°32′ S). Rodent frequencies in S. densiflora were positively correlated with crab densities throughout the low and middle marsh. Additionally, the highest quality of S. densiflora and inflorescence density was recorded at the highest crab densities. Experimental manipulation of crab densities shows that N. granulata indirectly enhances the performance of S. densiflora (e.g., decreased fiber content and C/N ratios) and increases density of seeds. Moreover, N. granulata also facilitates S. densiflora seed availability to rodents by concentrating them in sediment mound at their burrows entrances. Experimental rodent exclusions showed that rodent species used S. densiflora seeds, a variable positively related to crab burrow density. Thus, our results show that N. granulata drives the granivorous rodent distribution and the intensity of seeds–rodent interaction trough facilitative and indirect interactions in marsh community.     

Toxicity of vegetable tannin extract from <Emphasis Type="Italic">Acacia mearnsii</Emphasis> in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

Vegetable tannins are complex polyphenols, which occur widely in nature. Traditionally, natural tannins have been used for tanning leather. In Brazil, the main tannin-based products are obtained from Acacia mearnsii, which is a leguminous tree native to Southeastern of Australia, and the first seeds were brought to Brazil in 1928. The main cultivation of acacia was established in Rio Grande do Sul state due to the possibility of raw material for charcoal, adhesives to fuel and for tanning leather. The leather tanning processes based on plant tannins are thought to be less harmful than chromium-based tanning, and it has been used as a sustainable alternative. However, there is scarce information about the environmental impact of the leather tanning processes, with most studies reporting inhibitory effects against microorganisms at high doses and stimulatory and positive health effects at low concentrations. The aim of this study was to evaluate the toxicity of tannin preparations extracted from A. mearnsii in Saccharomyces cerevisiae. Vegetable tannin toxicity in yeast was tested using two tannin treatments in different concentrations. In general, the results showed toxicity of vegetable in yeast, BY4741 and gsh1Δ strains.     

Hybridization and Plasticity Contribute to Divergence Among Coastal and Wetland Populations of Invasive Hybrid Japanese Knotweed <Emphasis Type="Italic">s</Emphasis>.<Emphasis Type="Italic">l</Emphasis>. (<Emphasis Type="Italic">Fallopia</Emphasis> spp.)

Japanese knotweed s.l. (Fallopia spp.) is a highly invasive clonal plant, best known from roadside and riparian habitats. Its expansion into beaches on Long Island, NY, USA, represents a major habitat shift. I surveyed populations from beaches and wetlands and conducted a common garden experiment to test for variation in drought tolerance and phenotype among populations and habitats. All populations were composed mostly of first- and later-generation hybrids. I found significant variation among populations in growth, lamina size, specific leaf area (SLA), and biomass allocation, in both the field and the common garden. Lamina size, growth, and root-to-shoot responded plastically to drought treatment. Wetland populations tolerated drought as well as beach populations. Differentiation in SLA between habitats suggests that some selection for beach genotypes may have occurred. It appears that both hybridization and phenotypic plasticity are contributing to the expansion of Fallopia spp. into novel habitat.     

<Emphasis Type="Italic">An </Emphasis><Emphasis Type="Italic">Inconvenient Truth</Emphasis>: a focus on its portrayal of the hydrologic cycle

An Inconvenient Truth (AIT) has earned Al Gore an Oscar and a share of the 2007 Nobel Peace Prize and has been widely acclaimed by the mass media. However, significant errors exist in the film, owing to alarmism and exaggeration. As this forum does not provide for a detailed examination of these errors, this paper will focus only on the portrayal of the hydrologic cycle by AIT—precipitation and floods, soil moisture and droughts, and storminess. AIT argues that precipitation and intense rainfalls, floods, droughts, and the total number, intensity, and duration of tropical cyclones have all increased due exclusively to anthropogenically-driven climate change; indeed, AIT paints a picture of near scientific certainty with an overwhelming bias toward catastrophe scenarios. A closer look at the science, however, reveals that the data do not support these claims and that the scientific community is divided as to what the impact of anthropogenic climate change on the hydrologic cycle will be. Thus, the film gives a false impression of both the current state of climate change and that ‘the science is settled’.

Phytotoxicity test applied to sewage sludge using <Emphasis Type="Italic">Lactuca sativa</Emphasis> L. and <Emphasis Type="Italic">Lepidium sativum</Emphasis> L. seeds

Sewage sludge from wastewater treatment plants (WWTPs) has increased in recent years in Spain and Europe in general. Agriculture seems a viable solution when seeking alternatives for its final disposal. Sewage sludge reuse can, however, pose risks given presence of heavy metals, pathogen microorganisms or toxic compounds, which must be controlled to minimize risks for human health and the environment. In the present study, the phytotoxicity of sewage sludge from the Alcázar de San Juan WWTP using two types of seeds (Lactuca sativa L. and Lepidium sativum L.) in bioassays was analyzed. The relative germination rates (RGP), relative radicle growth (RRG) and germination index were determined for both species. Hypocotyl length was measured in lettuce. Negative (distilled water) and positive (zinc sulfate) controls were prepared. Depending on the biological material and residue phytotoxicity dose, analyses can be modified given the different sensitivities of plants. Lepidium sativum L. was more sensitive to phytotoxic compounds than Lactuca sativa L. Hypocotyl measurements provide complementary toxicity information. A general agreement between authors and researchers to standardize this type of analysis would be useful to make criteria uniform.     

Physiological Constraints in Juvenile <Emphasis Type="Italic">Ostrea chilensis</Emphasis> Fed the Toxic Dinoflagellate <Emphasis Type="Italic">Alexandrium catenella</Emphasis>

Frequent blooms of the dinoflagellate Alexandrium catenella in southern Chile encouraged undertaking the present study which uses the oyster Ostrea chilensis as a model for evaluating the feeding, growth, lipid storage and mortality responses to diets containing paralytic shellfish poisoning (PSP) produced by A. catenella. Medium-term (30 days) physiological responses of two groups of juvenile oysters were measured every 10 days. Five replicates were exposed to diets containing A. catenella and other five replicates were fed with a diet containing the non-toxic algae Isochrysis galbana. Diets were continuously supplied at a concentration of 2 mg L^?1, in which the feeding and metabolic activity was measured, and the scope for growth calculated. Lipids storage, actual growth and mortality were also measured every 10 days. The results showed that the toxic diet has dramatic negative effects on feeding and metabolism of the juvenile individuals of O. chilensis, with high reduction of the lipid storage and growth. Mortality was also increased in individuals fed with the contaminated diet. This study supports the conclusion that the toxic dinoflagellate A. catenella restricts the energy acquisition in the juvenile O. chilensis, an important fishery and aquaculture resource in southern Chile.     

Discovery of <Emphasis Type="Italic">Elephas</Emphasis> cf. <Emphasis Type="Italic">namadicus</Emphasis> from the late Pleistocene strata of Marginal Ganga Plain

We describe an elephant skull recovered from a cliff section of Dhasan river of Marginal Ganga Plain. The dental morphology and cranial features of the skull have been compared with the known species of Elephas from the Indian subcontinent. Although it shows very near resemblance to Elephas namadicus, but being an isolated specimen its specific identity cannot be proclaimed with certainty. As such, the specimen is provisionally referred as E. cf. namadicus. The Optically Stimulated Luminescence ages place this find at ~56 ka BP. This is the first chronologically well constrained report of E. cf. namadicus from the Ganga Plain.     

Toxinogenicity and cytotoxicity of <Emphasis Type="Italic">Alternaria,Aspergillus</Emphasis> and <Emphasis Type="Italic">Penicillium</Emphasis> moulds isolated from working environments

There is currently limited research available on the secondary metabolites of moulds in workplaces. The aim of this study was to determine the mould contamination in museums (N = 4), composting plants (N = 4) and tanneries (N = 4) and the secondary metabolite profiles of Alternaria, Aspergillus and Penicillium isolates from these workplaces. Alternaria, Aspergillus and Penicillium species were identified using the ITS1/2 sequence of the rDNA region. Mould metabolites were quantitatively analysed on standard laboratory medium and mineral medium containing materials specific to each workplace using liquid chromatography-mass spectrometry. We also examined the cytotoxicity of the moulds using MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assays. Air microbiological contamination analyses showed a number of microorganisms, ranging from 2.4 × 10³ CFU m^?3 (composting plants) to 6.8 × 10⁴ CFU m^?3 (tanneries). We identified high percentages of Alternaria, Aspergillus and Penicillium moulds (air 57–59%, surfaces 10–65%) in all workplaces. The following moulds were the most cytotoxic (>90%): Alternaria alternata, A. limoniasperae, Aspergillus flavus, Penicillium biourgeianum, P. commune and P. spinulosum. The same mould species isolated from different working environments exhibited varying toxigenic and cytotoxic properties. Modifying the culture medium to simulate environmental conditions most often resulted in the inhibition of secondary metabolite production. Moulds isolated from the working environments produced the following mycotoxins (ng g^?1): chanoclavines (0.28–204), cyclopiazonic acid (27.1–1045), fumigaclavines (0.33–10,640,000), meleagrin (0.57–13,393), roquefortins (0.01–16,660), rugulovasines (112–220), viridicatin (0.12–957), viridicatol (4.23–2753) and quinocitrinines (0.07–1104), which may have a negative impact on human health.     

Biodegradation of ortho-dimethyl phthalate by a binary culture of <Emphasis Type="Italic">Variovorax</Emphasis> sp. BS1 and <Emphasis Type="Italic">Achromobacter denitrificans</Emphasis>

Binary mixture of Variovorax sp. BS1 and Achromobacter denitrificans degraded >99 % of 300 mg l^?1 of ortho-dimethyl phthalate (DMP) within 24 h of incubation at 30 °C. Rate of degradation of DMP followed the order: A. denitrificans > binary mixture > Variovorax sp. BS1. Transient intermediate metabolites were not detected using HPLC analyses at any time points using Variovorax sp. BS1 and binary mixture. However, using pure culture of A. denitrificans, monomethyl phthalate was accumulated during the course of DMP biodegradation which disappeared with time of incubation. Binary mixture of Variovorax sp. BS1 and A. denitrificans exhibited better efficiency in terms of biodegradation of DMP as compared to either individual bacterial strain. In addition, fluorescence in situ hybridization technique was used to estimate the population dynamics of Variovorax sp. BS1 in binary mixture. A. denitrificans in mixed culture were estimated by subtracting total number of cells of Variovorax sp. BS1 from the total counts of microbial cells using an epifluorescence microscope after staining with 4′,6-diamidino-2-phenylindole. Results obtained at mid-exponential growth phase suggested the abundance of both bacterial strains as primary degraders.     

Ecophysiology of the Olympia Oyster, <Emphasis Type="Italic">Ostrea lurida</Emphasis>, and Pacific Oyster, <Emphasis Type="Italic">Crassostrea gigas</Emphasis>

The native Olympia oyster, Ostrea lurida, was once abundant in many US Pacific Northwest (PNW) estuaries, but was decimated by human activity in the late nineteenth early to twentieth centuries. Having been the subject of only few modern, detailed studies, a dearth of basic physiological information surrounded O. lurida and how it compared to the now dominant, non-native Pacific oyster, Crassostrea gigas. Utilizing laboratory and in situ studies in Yaquina Bay, OR, we explored the clearance rates of both species across a wide range of conditions. Pacific oysters not only had greater size-specific clearance rates than Olympia oysters, but also had a lower optimum temperature. Clearance rates for both species were reduced at lower salinity, at lower organic content, and at higher turbidity. Clearance rate models were constructed for each species using three approaches: (1) a single mechanistic model that incorporated feeding response functions of each species to the effects of temperature, salinity, turbidity, and seston organic content based on laboratory studies; (2) another additive model in which the number and type of response functions from laboratory studies were allowed to vary; and (3) a statistical model that utilized environmental data collected during in situ feeding trials. Clearance rate models that correlated feeding activity with in situ environmental data were found to often better predict oyster clearance rates (based on Adj R ²) for both species in Yaquina Bay, OR, than mechanistic, additive models based on laboratory feeding response functions; however, in situ correlative models varied in accuracy by species and season. This work represents important first steps towards better understanding the physiological ecology of the native Olympia oyster and how it differs from introduced and now dominant Pacific oyster.     

Life and death of <Emphasis Type="Italic">Saccocoma tenella</Emphasis> (G<Emphasis Type="SmallCaps">oldfuss</Emphasis>)

The morphology of the small stalkless Saccocoma tenella is unique among crinoids. It is characterized by an extremely light skeleton with dish-like lateral wings on the proximal brachials and peculiar paired vertical processes flanking the food grooves of more distal brachials. The arms are heavily branched. The lateral wings obviously were involved in vertical movement. For the vertical processes a “baffle rail” function for arm curling and “snap swimming” has been postulated, with muscles between the processes. However, there is no evidence that the processes were connected by muscles. For food collection a “pulsating funnel” model in the water column is advocated, with the processes serving to collect plankton during upward movement of the arms. The resulting mouth-up position is supported by the biostratinomy. Saccocoma tenella is considered to have been pelagic, a benthic lifestyle is rejected on ecologic and taphonomic grounds. Adorally-curled arms are considered a reaction to hostile environment before death, not a taphonomic artefact.     

Feeding Behavior of the Native Mussel <Emphasis Type="Italic">Ischadium recurvum</Emphasis> and the Invasive Mussels <Emphasis Type="Italic">Mytella charruana</Emphasis> and <Emphasis Type="Italic">Perna viridis</Emphasis> in FL,USA, Across a Salinity Gradient

The feeding behavior of three species of mussels, the native Ischadium recurvum and the invasives Mytella charruana and Perna viridis, was studied in an invaded ecosystem in Florida (USA). In situ feeding experiments using the biodeposition method were performed along a salinity gradient in four different locations along the St. Johns River. Water characteristics, such as salinity, temperature, dissolved oxygen, and seston loads, were recorded to identify relationships between these variables and the feeding behavior of the mussels. Feeding behavior of the species varied by study site. Clearance, filtration, organic ingestion, and absorption rates of I. recurvum were negatively affected by salinity. For the invasive mussel, M. charruana, rejection was positively related to salinity while total ingestion, organic ingestion, and absorption rates were positively related to the percentage of organic matter in the seston. For P. viridis, total and organic ingestion rates were negatively affected by salinity but positively affected by total particulate matter. Condition indices for P. viridis and M. charruana were 13.16?±?0.64 and 6.63?±?0.43, respectively, compared to 4.82?±?0.41 for the native species I. recurvum, indicating that these mussels are well adapted to the environmental conditions in the area. This study indicates that the three species have different preferred habitats because of their specific responses to water characteristics. Thus, the invasive mussels will not totally occupy the niche of the native mussel in Florida despite overlapping zones. These data may help identify potential invaded areas and understand the extent of the invasion.     

Utilization of <Emphasis Type="Italic">Spartina</Emphasis>- and <Emphasis Type="Italic">Phragmites</Emphasis>-Derived Dissolved Organic Matter by Bacteria and Ribbed Mussels (<Emphasis Type="Italic">Geukensia demissa</Emphasis>) from Delaware Bay Salt Marshes

Phragmites australis has been invading Spartina-alterniflora-dominated salt marshes throughout the mid-Atlantic. Although, Phragmites has high rates of primary production, it is not known whether this species supports lower trophic levels of a marsh food web in the same manner as Spartina. Using several related photochemical and biological assays, we compared patterns of organic matter flow of plant primary production through a key salt marsh metazoan, the ribbed mussel (Geukensia demissa), using a bacterial intermediate. Dissolved organic matter (DOM) was derived from plants collected from a Delaware Bay salt marsh and grown in the laboratory with ¹⁴C-CO₂. Bacterial utilization of plant-derived DOM measured as carbon mineralization revealed that both species provided bioavailable DOM to native salt marsh bacteria. Total carbon mineralization after 19 days was higher for Spartina treatments (36% ¹⁴CO₂ ± 3 SE) compared with Phragmites treatments (29% ±2 SE; Wilcoxon–Kruskal–Wallis rank sums test, P < 0.01). Pre-exposing DOM to natural sunlight only enhanced or decreased bioavailability of the DOM to the bacterioplankton during initial measurements (e.g., 7 days or less) but these differences were not significant over the course of the incubations. Mixtures of ¹⁴C-labeled bacterioplankton (and possibly organic flocs) from ¹⁴C-DOM treatments were cleared by G. demissa at similar rates between Spartina and Phragmites treatments. Moreover, ¹⁴C assimilation efficiencies for material ingested by mussels were high for both plant sources ranging from 74% to 90% and not significantly different between plant sources. Sunlight exposure did not affect the nutritional value of the bacterioplankton DOM assemblage for mussels. There are many possible trophic and habitat differences between Spartina- and Phragmites-dominated marshes that could affect G. demissa but the fate of vascular plant dissolved organic carbon in the DOM to bacterioplankton to mussel trophic pathway appears comparable between these marsh types.