Journal articles on the topic 'Microcosmos 3.0'

O objetivo deste trabalho foi estudar a importância da minhoca Pontoscolex corethrurus na distribuição do pesticida dicofol em um Argissolo. Como modelo foram utilizados microcosmos contendo solo tamizado e acondicionado na densidade 1,25 g cm-3. Em microcosmos com e sem Pontoscolex corethurus, foram aplicados 14C-dicofol, e após um período de 52 dias fez-se uma simulação de chuvas torrenciais. Na camada de 0-1 cm, recuperou-se 75% da radioatividade no solo sem minhoca, e no solo com minhoca, a recuperação foi 9% inferior. Nas camadas mais profundas, os valores da radioatividade ficaram abaixo de 20%, e as diferenças entre os tratamentos não ultrapassaram 2%. Esta espécie de minhoca, muito freqüente no Brasil, mostrou não ter influência relevante na distribuição do pesticida no solo.

La bioestimulación es una metodología aceptada para promover la biorremediación de hidrocarburos en un suelo. El objetivo del presente trabajo fue optimizar la relación C:N:P, humedad y concentración y tipo de hidrocarburos para estudiar la viabilidad de un proceso de biodegradación de hidrocarburos en un suelo de la ciudad de Río Gallegos, Argentina. Se realizaron cuatro bioensayos utilizando microcosmos para determinar las condiciones de C:N:P (100:7.5:0.75, 100:5:0.5, 100:2.5:0.25 and 100:1:0.1), humedad (0% - 15 %), concentración de hidrocarburos (0% - 5 %) y tipo de contaminante para mejorar la eficiencia de la biorremediación. La monitorización de los experimentos incluyó la mineralización y cuantificación de hidrocarburos y de bacterias heterótrofas y degradadoras de hidrocarburos. Los resultados demostraron que la relación C:N:P óptima fue de 100:2.5:0.25, con un rango de incorporación de humedad de entre 10-15% para un suelo con 3% de hidrocarburos. Se observó que con la aplicación de una adecuada bioestimulación, la biorremediación puede ser efectiva, estimándose que los hidrocarburos de la nafta podrán volatilizarse generando una inhibición de la actividad bacteriana. Los resultados también mostraron que cuando los hidrocarburos de la nafta son eliminados del suelo en un 100%, la actividad bacteriana puede recuperarse y desarrollar la biodegradación del gasoil, y en menor medida los del aceite, brindando esto un panorama auspicioso para la aplicación de esta tecnología a gran escala en la región.

Abstract. An experiment comparing effects of sulphuric acid and reduced N deposition on soil water quality and on chemical and physical growth indicators for forest ecosystems is described. Six H2SO4 and (NH4)2SO4 treatment loads, from 0 – 44 and 0 – 25 kmolc ha-1 yr-1, respectively, were applied to outdoor microcosms of Pinus sylvestris seedlings in 3 acid to intermediate upland soils (calc-silicate, quartzite and granite) for 2 years. Different soil types responded similarly to H2SO4 loads, resulting in decreased leachate pH, but differently to reduced N inputs. In microcosms of calc-silicate soil, nitrification of NH4 resulted in lower pH and higher cation leaching than in acid treatments. By contrast, in quartzite and granite soils, (NH4)2SO4 promoted direct cation leaching, although leachate pH increased. The results highlighted the importance of soil composition on the nature of the cations leached, the SO4 adsorption capacities and microbial N transformations. Greater seedling growth on calc-silicate soils under both treatment types was related to sustained nutrient availability. Reductions in foliar P and Mg with higher N treatments were observed for seedlings in the calc-silicate soil. There were few treatment effects on quartzite and granite microcosm tree seedlings since P limitation precluded seedling growth responses to treatments. Hence, any benefits of N deposition to seedlings on quartzite and granite soils appeared limited by availability of co-nutrients, exacerbated by rapid depletion of soil exchangeable base cations. Keywords: acidification, manipulation, nitrogen, ammonium, deposition, soil, drainage, pine, microcosms, forest

ABSTRACT Use and transport of petroleum products can result in serious contamination of freshwater habitats via leakage, spills, aerosols, and runoff. Little development of bioremediation strategies has occurred for enhancing degradation of petroleum products in situations involving contamination of freshwater wetland ecosystems. The objective of this study was to investigate different inorganic mineral nutrients for their ability to enhance biodegradation of crude oil in contaminated wetlands on a microcosm scale. Aquaria of 10-gallon capacity, filled with wetland soil and planted with species of emergent wetland plants, were used to simulate natural wetlands. Two levels of water coverage were studied: (1) water level even with soil surface, and (2) water level 10 cm above the soil surface. Six treatments were evaluated in duplicate for each water level: unoiled, no-nutrient control; oiled + no nutrient control; oiled + nitrate addition; oiled + nitrate + phosphate addition; oiled + ammonia addition; and oiled + ammonia + phosphate addition. Thus, 24 aquaria were set up for each sampling event (0, 2, 4, 8, 16, and 32 weeks) totaling 144 aquaria. Nutrients were applied once each week. Nitrate, ammonia, dissolved oxygen, pH, temperature, and conductivity were measured before and after nutrient addition. Biodegradation was tracked by GC/MS analysis of hopane-normalized crude oil components from the sacrificed aquaria over the 32-week experimental period. Results indicated that: (1) the rates of biodegradation of the alkanes and PAHs (polycyclic aromatic hydrocarbons) were higher for all treatments in the high-water level microcosms compared with the low-water level microcosms; (2) the highest rates of alkane and PAH degradation were measured in the high-water level microcosms receiving nitrate and phosphate; (3) the treatments with nitrate and phosphate showed nearly a 90% reduction of alkanes and a 50% reduction of PAHs as compared to nearly a 50% reduction of alkanes and 40% reduction of PAHs by the oil with no nutrients control for the high-water level; (4) the nitrate and phosphate addition treatments, for both water levels, showed good plant growth and the highest plant and root densities as compared to the other treatments. This information is being used in the design of a mesoscale experiment as part of the second phase of this study.

Texture affects pore space, bacterial and protozoan populations and their activity in soil. The objective of this study was to test the hypothesis that protozoa grazing on bacteria increase the mineralization of bacterial C and N more in coarse-textured soils than in fine-textured soils. The microcosm experiment consisted of samples from three sterilized Orthic Black Chernozemic soils (SiC, CL and SL) inoculated with Pseudomonos bacteria, two treatments (with and without protozoa), and five sampling dates. The Pseudomonas population was labelled in situ by adding glucose- 14C and KNO3-15N (day 0). A species of Acanthamoeba was added to the microcosms on Day 2. On Day 4 bacterial numbers in all three soils were approximately 3 × 109 g−1 soil. The greatest reduction of bacteria due to protozoan grazing occurred between day 4 and day 7. All soils showed increased CO2-14C evolution and NH4-15N mineralization due to protozoan grazing but the mineralization rate of labelled N in the SL soil was much greater than in the fine-textured soils. The effect of texture on protozoan grazing was not as marked between day 12 and day 37 as earlier in the incubation. Protozoan-induced effects were transient in the soils studied and were most apparent in the coarse-textured soil. Key words: 14C, 15N, N mineralization-immobilization, bacteria, organic matter, Typic Cryoboroll, porosity, protozoa

The influence of different curing conditions on hydration properties of fluorgypsum products formed by semi-dry pressing was studied. Laboratory experiments were conducted to investigate the compressive strength development, content of crystal water, and microcosmic crystal structure when four curing methods (nature curing, curing in standard curing chamber, soaked in water 3 min every other day or every day) and five curing temperatures (-20 °C, 0 °C, 10 °C, 20 °C, 35 °C) were used. The results indicated that the hydration properties of fluorgypsum products could be improved under proper curing methods and lower curing temperature.

ABSTRACTPalsa peats are characterized by elevated, circular frost heaves (peat soil on top of a permanently frozen ice lens) and are strong to moderate sources or even temporary sinks for the greenhouse gas nitrous oxide (N2O). Palsa peats are predicted to react sensitively to global warming. The acidic palsa peat Skalluvaara (approximate pH 4.4) is located in the discontinuous permafrost zone in northwestern Finnish Lapland.In situN2O fluxes were spatially variable, ranging from 0.01 to −0.02 μmol of N2O m−2h−1. Fertilization with nitrate stimulatedin situN2O emissions and N2O production in anoxic microcosms without apparent delay. N2O was subsequently consumed in microcosms. Maximal reaction velocities (vmax) of nitrate-dependent denitrification approximated 3 and 1 nmol of N2O per h per gram (dry weight [gDW]) in soil from 0 to 20 cm and below 20 cm of depth, respectively.vmaxvalues of nitrite-dependent denitrification were 2- to 5-fold higher than thevmaxnitrate-dependent denitrification, andvmaxof N2O consumption was 1- to 6-fold higher than that of nitrite-dependent denitrification, highlighting a high N2O consumption potential. Up to 12 species-level operational taxonomic units (OTUs) ofnarG,nirKandnirS, andnosZwere retrieved. Detected OTUs suggested the presence of diverse uncultured soil denitrifiers and dissimilatory nitrate reducers, hitherto undetected species, as well asActino-,Alpha-, andBetaproteobacteria. Copy numbers ofnirSalways outnumbered those ofnirKby 2 orders of magnitude. Copy numbers ofnirStended to be higher, while copy numbers ofnarGandnosZtended to be lower in 0- to 20-cm soil than in soil below 20 cm. The collective data suggest that (i) the source and sink functions of palsa peat soils for N2O are associated with denitrification, (ii) actinobacterial nitrate reducers andnirS-type andnosZ-harboring proteobacterial denitrifiers are important players, and (iii) acidic soils like palsa peats represent reservoirs of diverse acid-tolerant denitrifiers associated with N2O fluxes.

AbstractBacteria and fungi from pristine soil, never exposed to glufosinate herbicide, were isolated and analyzed for glufosinate tolerance. Seven of the 15 tested isolates were sensitive to 1 mM glufosinate (an active ingredient of many nonselective contact herbicides), 5 were resistant to 4 mM glufosinate and 3 even to 8 mM glufosinate in liquid medium. None of the isolated microorganisms carried the gene for glufosinate resistance bar (bialaphos resistance) in its genome and at least in some of glufosinate-resistant isolates the increased glutamine synthetase level was detected as a possible resistance mechanism. The transfer of the bar glufosinate resistance gene from transgenic maize Bt 176 into glufosinate-sensitive soil bacterium Bacillus pumilus S1 was not detected under the laboratory conditions by a classical plate count method and PCR. The ecological risk of potential bar gene transfer from genetically modified plants into soil microcosms under natural circumstances is discussed.

A bacterial strain, designated strain LP01T, was isolated from a laboratory-scale microcosm packed with a mixture of soil and sewage sludge compost designed to study the evolution of microbial biodiversity over time. The bacterial strain was selected for its potential ability to store polyhydroxyalkanoates (PHAs) as intracellular granules. The cells were aerobic, Gram-stain-negative, non-endospore-forming motile rods. Phylogenetically, the strain was classified within the genus Massilia , as its 16S rRNA gene sequence had similarity of 99.2 % with respect to those of Massilia albidiflava DSM 17472T and M. lutea DSM 17473T. DNA–DNA hybridization showed low relatedness of strain LP01T to the type strains of other, phylogenetically related species of the genus Massilia . It contained Q-8 as the predominant ubiquinone and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) as the major fatty acid(s). It was found to contain small amounts of the fatty acids C18 : 0 and C14 : 0 2-OH, a feature that served to distinguish it from its closest phylogenetic relatives within the genus Massilia . The DNA G+C content was 66.0 mol%. Phylogenetic, phenotypic and chemotaxonomic data obtained in this study suggest that strain LP01T represents a novel species of the genus Massilia , for which the name Massilia umbonata sp. nov. is proposed. The type strain is LP01T ( = CECT 7753T = DSM 26121T).

Disposal in a geological disposal facility (GDF) is the preferred route for the world's growing inventory of nuclear wastes. Bentonite clay is a common component of the engineered barrier system, serving to isolate and stabilise the high heat-generating waste packages in the geosphere (Stroes-Gascoyne et al. 2010).Bentonites naturally contain sulfate-reducing bacteria (SRB) (Haynes et al. 2021), which in the presence of the correct substrates, produce H₂S that is highly corrosive to metals (such as steel waste packages). Sulfate, the electron acceptor, is present in most groundwaters, and the corrosion of steel produces hydrogen, an electron donor (Bagnoud et al. 2016). Compacting bentonite on deposition can restrict GDF microbial activity, since swelling pressures upon saturation restrict the available porosity for microbes (Masurat et al. 2010). Additionally, groundwater chemical conditions may impact bentonite mechanical properties (e.g., the effect of salinity on swelling capacity (He et al. 2019), and the energetics of bacterial metabolism (Oren 1999).This work uses bentonite SRB enrichment cultures to assess parameters that control microbial metabolism, and the relative contribution of microbially influenced corrosion (MIC), versus chemical corrosion of steel (Fig. 1). This will provide evidence to underpin lines of argument and models used in the safety assessments for geological disposal. Experiments described include microcosm incubations containing bentonite slurries across a range of salinity, and pressure cell bioreactors to evaluate the above conditions in the context of a compacted bentonite barrier system. Initial results show that in the presence of lactate as an electron donor, slurry systems with bentonite, low-carbon steel and sulfate-containing groundwater provide the essential nutrients for the proliferation of an MIC-inducing community (Fig. 2). Experiments have also shown that in such systems, increasing the groundwater NaCl concentration inhibits microbial activity during the 3-month experimental duration.Additionally, SRB have been shown to reduce priority radionuclides, such as selenium (Nancharaiah and Lens 2015). Selenium is a priority radionuclide in high-level waste, and in its highest oxidation states, selenate (Se(VI)) and selenite (Se(IV)), it is highly soluble and therefore mobile in the environment. Early experiments have shown that when an electron donor is present in microcosms containing bentonite and groundwater, bentonite-native SRB may be capable of reducing soluble selenium down to insoluble Se(0), restricting its environmental mobility.

Thiamethoxam, a systemic novel insecticide, is a foliar and seed treatment formulation. However, studies on the potential microorganisms for its bioremediation are least explored. Similarly, the sublethal ill effects of thiamethoxam on native soil microflora have also not been studied. Hence, Pseudomonas fluorescens, a plant growth-promoting rhizobacterium, was evaluated for its ability to bioremediate thiamethoxam, known for its relatively longer half-life in soil. Survivability of P. fluorescens was determined in the minimal salt and half-strength nutrient broth media contaminated with thiamethoxam in the range of 5-100 mg/L for 21 days, and maximum growth in terms of optical density was observed on 3rd day after inoculation at 10 mg/L (0.86-1.00 AU) in half-strength nutrient broth. The bacterium's ability to bioremediate thiamethoxam in the presence of biostimulants such as vermicompost and vesicular-arbuscular mycorrhiza (VAM) was evaluated through soil microcosms studies conducted under laboratory conditions for 21 days. Soil microcosms fortified with thiamethoxam at 10 mg/L were treated with P. fluorescens alone and in combination with vermicompost and VAM, and the half-life of thiamethoxam was calculated from residual concentration in soil extracts on 0, 3, 7, 14, and 21days. The results indicated that the combined application of VAM with P. fluorescens exhibited the shortest halflife of thiamethoxam (31.5 days) compared to natural attenuation (86.6 days). The impact of thiamethoxam on soil microbial activity was assessed by the enzymatic activity of acid/alkaline phosphatases, dehydrogenases, and β-D glucosidases in soil, and the results revealed the adverse effect of thiamethoxam on soil microflora with relatively lower measured values in contaminated soils for all the enzymes under the study compared to uncontaminated control.. KEYWORDS :Bioremediation, Biostimulants, Enzyme activity, PGPR, Pseudomonas, fluorescens, Thiamethoxam

ABSTRACT Removal of potential pathogenic bacteria, for example, during wastewater treatment, is effected by sorption, filtration, natural die-off, lysis by viruses, and grazing by protists, but the actual contribution of grazing has never been assessed quantitatively. A methodical approach for analyzing the grazing of protists on 13C-labeled prey bacteria was developed which enables mass balances of the carbon turnover to be drawn, including yield estimation. Model experiments for validating the approach were performed in closed microcosms with the ciliate Uronema sp. and 13C-labeled Escherichia coli as model prey. The transfer of bacterial 13C into grazing protist biomass was investigated by fatty acid (FA) and RNA stable isotope probing (SIP). Uronema sp. showed ingestion rates of ∼390 bacteria protist−1 h−1, and the temporal patterns of 13C assimilation from the prey bacteria to the protist FA were identified. Nine fatty acids specific for Uronema sp. were found (20:0, i20:0, 22:0, 24:0, 20:1ω9c, 20:1ω9t, 22:1ω9c, 22:1ω9t, and 24:1). Four of these fatty acids (22:0, 20:1ω9t, 22:1ω9c, and 22:1ω9t) were enriched very rapidly after 3 h, indicating grazing on bacteria without concomitant cell division. Other fatty acids (20:0, i20:0, and 20:1ω9c) were found to be indicative of growth with cell division. The fatty acids were found to be labeled with a percentage of labeled carbon (atoms percent [atom%]) up to 50. Eighteen percent of the E. coli-derived 13C was incorporated into Uronema biomass, whereas 11% was mineralized. Around 5 mol bacterial carbon was necessary in order to produce 1 mol protist carbon (yx / s ≈ 0.2), and the temporal pattern of 13C labeling of protist rRNA was also shown. A consumption of around 1,000 prey bacteria (∼98 atom% 13C) per protist cell appears to be sufficient to provide detectable amounts of label in the protist RNA. The large shift in the buoyant density fraction of 13C-labeled protist RNA demonstrated a high incorporation of 13C, and reverse transcription-real-time PCR (RT-qPCR) confirmed that protist rRNA increasingly dominated in the heavy RNA fraction.

Temporal responses of indigenous bacterial populations and proteolytic enzyme (i.e., aminopeptidase) activities in the bacterioplankton assemblages from 3 separate freshwater environments were examined after exposure to various zinc (Zn) concentrations under controlled microcosm conditions. Zn concentrations (ranging from 0 to 10 μmol/L) were added to water samples collected from the Kalamazoo River, Rice Creek, and Huron River and examined for bacterial abundance and aminopeptidase activities at various time intervals over a 48 h incubation period in the dark. The results showed that the Zn concentrations did not significantly influence total bacterial counts directly; however, aminopeptidase activities varied significantly to increasing zinc treatments over time. Also, analysis of variance and linear regression analyses revealed significant positive relationships between bacterial numbers and their hydrolytic enzyme activities, suggesting that both probably co-vary with increasing Zn concentrations in aquatic systems. The results from this study serve as additional evidence of the ecological role of Zn as an extracellular peptidase cofactor on the dynamics of bacterial assemblages in aquatic environments.

Microbial communities living in Sphagnum are known to constitute early indicators of ecosystem disturbances, but little is known about their response (including their trophic relationships) to climate change. A microcosm experiment was designed to test the effects of a temperature gradient (15, 20, and 25 °C) on microbial communities including different trophic groups (primary producers, decomposers, and unicellular predators) in Sphagnum segments (0–3 cm and 3–6 cm of the capitulum). Relationships between microbial communities and abiotic factors (pH, conductivity, temperature, and polyphenols) were also studied. The density and the biomass of testate amoebae in Sphagnum upper segments increased and their community structure changed in heated treatments. The biomass of testate amoebae was linked to the biomass of bacteria and to the total biomass of other groups added and, thus, suggests that indirect effects on the food web structure occurred. Redundancy analysis revealed that microbial assemblages differed strongly in Sphagnum upper segments along a temperature gradient in relation to abiotic factors. The sensitivity of these assemblages made them interesting indicators of climate change. Phenolic compounds represented an important explicative factor in microbial assemblages and outlined the potential direct and (or) indirect effects of phenolics on microbial communities.

Eutrophication of the planet’s aquatic systems is increasing at an unprecedented rate. In freshwater systems, nitrate—one of the nutrients responsible for eutrophication—is linked to biodiversity losses and ecosystem degradation. One of the main sources of freshwater nitrate pollution in New Zealand is agriculture. New Zealand’s pastoral farming system relies heavily on the application of chemical fertilisers. These fertilisers in combination with animal urine, also high in nitrogen, result in high rates of nitrogen leaching into adjacent aquatic systems. In addition to nitrogen, livestock waste commonly carries human and animal enteropathogenic bacteria, many of which can survive in freshwater environments. Two strains of enteropathogenic bacteria found in New Zealand cattle, are K99 and Shiga-toxin producing Escherichia coli (STEC). To better understand the effects of ambient nitrate concentrations in the water column on environmental enteropathogenic bacteria survival, a microcosm experiment with three nitrate-nitrogen concentrations (0, 1, and 3 mg NO3-N /L), two enteropathogenic bacterial strains (STEC O26—human, and K99—animal), and two water types (sterile and containing natural microbiota) was run. Both STEC O26 and K99 reached 500 CFU/10 ml in both water types at all three nitrate concentrations within 24 hours and remained at those levels for the full 91 days of the experiment. Although enteropathogenic strains showed no response to water column nitrate concentrations, the survival of background Escherichia coli, imported as part of the in-stream microbiota did, surviving longer in 1 and 3 mg NO3-N/Lconcentrations (P < 0.001). While further work is needed to fully understand how nitrate enrichment and in-stream microbiota may affect the viability of human and animal pathogens in freshwater systems, it is clear that these two New Zealand strains of STEC O26 and K99 can persist in river water for extended periods alongside some natural microbiota.

The upflow anaerobic sludge blanket (UASB) reactor is a microcosm for the methanogenic degradation of organic matter in anaerobic environments, and depends on the auto-formation of dense 3D biofilms of 1–3 mm in diameter, referred to as granular sludge (biogranules). Past research has shown that UASB and other methanogenic reactors are extremely stable functionally, but the underlying basis of the functional stability is not well understood. In this study, microbial dynamics in the communities residing in UASB biogranules were analysed to determine responses to short-term perturbations (change in reactor feed). The reactor was fed with simulated brewery wastewater (SBWW) for 1.5 months (phase 1), acetate/sulfate for 2 months (phase 2), acetate alone for 3 months (phase 3) and then a return to SBWW for 2 months (phase 4). Analysis of 16S rRNA, methanogen-associated mcrA and sulfate reducer-associated dsrAB gene-based-clone libraries showed a relatively simple community composed mainly of the methanogenic archaea (Methanobacterium and Methanosaeta), members of the green non-sulfur (Chloroflexi) group of bacteria and Syntrophobacter, Spirochaeta, Acidobacteria and Cytophaga-related bacterial sequences. The mcrA clone libraries were dominated throughout by Methanobacterium- and Methanospirillum-related sequences. Although the reactor performance remained relatively stable throughout the experiment, community diversity levels generally decreased for all libraries in response to a change from SBWW to acetate alone feed. There was a large transitory increase noted in 16S diversity at the 2 month sampling on acetate alone, entirely related to an increase in bacterial diversity. Upon return to SBWW conditions in phase 4, all diversity measures returned to near phase 1 levels. Our results demonstrated that microbial communities, even highly structured ones such as in UASB biogranules, are very capable of responding to rapid and major changes in their environment.

Bioremediation is a promising strategy to remove crude oil contaminants. However, limited studies explored the potential of bacterial consortia on crude oil biodegradation in high salinity soil. In this study, four halotolerant strains (Pseudoxanthomonas sp. S1-2, Bacillus sp. S2-A, Dietzia sp. CN-3, and Acinetobacter sp. HC8-3S), with strong environmental tolerance (temperature, pH, and salinity), distinctive crude oil degradation, and beneficial biosurfactant production, were combined to construct a bacterial consortium. The inoculation of the consortium successfully degraded 97.1% of total petroleum hydrocarbons in 10 days, with notable removal of alkanes, cycloalkanes, branched alkanes, and aromatic hydrocarbons. Functional optimization showed that this consortium degraded crude oil effectively in a broad range of temperature (20–37 °C), pH (6–9), and salinity (0–100 g/L). In salt-enriched crude-oil-contaminated soil microcosms, the simultaneous treatment of bioaugmentation and biostimulation achieved the highest crude oil degradation rate of 568.6 mg/kg/d, compared to treatments involving abiotic factors, natural attenuation, biostimulation, and bioaugmentation after 60 days. Real-time PCR targeting the 16S rRNA and alkB genes showed the good adaptability and stability of this consortium. The degradation property of the constructed bacterial consortium and the engineered consortium strategy may have potential use in the bioremediation of crude oil pollution in high-salinity soil.

In this study, we show that noncoding sequences from amplified fragment length polymorphisms (AFLPs) can provide robust and sensitive genetic markers suitable for PCR-based discrimination of closely related strains of Bacillus and Paenibacillus , and quantitative PCR (qPCR)-based tracking of the strains in complex natural systems like soil. Quantitative PCR was accurate in the ~1 × 109 to ~1 × 104 colony forming units (CFU)/g soil range. The detection limit was improved to ~1 × 102 CFU/g when amplicons were analyzed by gel electrophoresis. Studies with laboratory-contained intact soil-core microcosms indicated that environmental persistence trends vary among different strains. For example, Bacillus circulans ATCC 9500, Bacillus amyloliquefaciens DSL 13563-0, Bacillus licheniformis ATCC 12713, Paenibacillus polymyxa NRRL B-4317, and 3 Bacillus subtilis strains (ATCC 6051A, ATCC 55405, and NRRL B-941) died down to below the 1 × 102 CFU/g detection limit by days 28–105. In contrast, over a 105-day period, B. licheniformis ATCC 55406, Bacillus megaterium NRRL B-14308, and P. polymyxa strains ATCC 55407 and DSL 13540-4 died down but persisted at levels just above the detection limit, whereas Bacillus thuringiensis ATCC 13367 experienced a less than 10-fold decrease in cell numbers.

Abstract. Here we report a time series of experiments performed in a microcosm to test the response of hypersaline microbial mats to diverse atmospheric CO2 conditions. Different from most part of the literature, our study used a sample chamber were carbon dioxide concentration was controlled. Our aim was to test the effect of different atmospheric CO2 conditions in benthic gross and net primary production, and respiration. This study showed for the first time to our knowledge absolute carbon limitation in a microbial mat. Oxygen concentration profile varied from a flattened shape to almost linear when atmospheric CO2 at the chamber reached 0 ppm, with NPP reaching 0 nmol cm−3 s−1 throughout most part of the profile. In this conditions sediment community respiration represented 100% of GPP. Extreme close coupling between primary production and respiration in microbial mats can be even self-sustainable in environments with temporally no atmospheric CO2 available. When submitted to even high CO2 concentrations (550 ppm), our sample showed a characteristic shape that indicate limitation composed by a more rectilinear oxygen profile, and NPP peaks mainly restricted to deeper layers. Therefore, we suggest that phototrophic communities in aquatic shallow ecosystems can be carbon limited. This limitation could be common especially in ecosystems submitted to variable water depth conditions, like coastal lagoons and intertidal sediments.

Abstract. An automated biogeochemical microcosm system allowing controlled variation of redox potential (EH) in soil suspensions was used to assess the effect of various factors on the mobility of mercury (Hg) as well as on the methylation of Hg in two contaminated floodplain soils with different Hg concentrations (approximately 5 mg kg−1 Hg and >30 mg kg−1 Hg). The experiment was conducted under stepwise variation from reducing (approximately −350 mV at pH 5) to oxidizing conditions (approximately 600 mV at pH 5). Results of phospholipid fatty acids (PLFA) analysis indicate the occurrence of sulfate reducing bacteria (SRB) such as Desulfobacter species (10me16:0, cy17:0, 10me18:0, cy19:0) or Desulfovibrio species (18:2ω6,9), which are considered to promote Hg methylation. The products of the methylation process are lipophilic, highly toxic methyl mercury species such as the monomethyl mercury ion [MeHg+], which is named as MeHg here. The ln(MeHg/Hgt) ratio is assumed to reflect the net production of monomethyl mercury normalized to total dissolved Hg (Hgt) concentration. This ratio increases with rising dissolved organic carbon (DOC) to Hgt ratio (lnDOC/lnHgt ratio) (R2 = 0.39, p < 0.0001, n = 63) whereas the relation between ln(MeHg/Hgt) ratio and lnDOC is weaker (R2 = 0.09; p < 0.05; n = 63). In conclusion, the DOC/Hgt ratio might be a more important factor for the Hg net methylation than DOC alone in the current study. Redox variations seem to affect the biogeochemical behavior of dissolved inorganic Hg species and MeHg indirectly through related changes in DOC, sulfur cycle, and microbial community structure whereas E,H and pH values, as well as concentration of dissolved Fe,3+/Fe2+ and Cl− seem to play subordinate roles in Hg mobilization and methylation under our experimental conditions.

The experiments on cellulose dissolution/regeneration have made some achievements to some extent, but the mechanism of cellulose regeneration in ionic liquids (ILs) and anti-solvent mixtures remains elusive. In this work, the cellulose regeneration mechanism in different anti-solvents, and at different temperatures and concentrations, has been studied with molecular dynamics (MD) simulations. The IL considered is 1-ethyl-3-methylimidazolium acetate (EmimOAc). In addition, to investigate the microcosmic effects of ILs and anti-solvents, EmimOAc-nH2O (n = 0–6) clusters have been optimized by Density Functional Theory (DFT) calculations. It can be found that water is beneficial to the regeneration of cellulose due to its strong polarity. The interactions between ILs and cellulose will become strong with the increase in temperature. The H-bonds of cellulose chains would increase with the rising concentrations of anti-solvents. The interaction energies between cellulose and the anions of ILs are stronger than that of cations. Furthermore, the anti-solvents possess a strong affinity for ILs, cation–anion pairs are dissociated to form H-bonds with anti-solvents, and the H-bonds between cellulose and ILs are destroyed to promote cellulose regeneration.

Abstract An experimental study in aquatic microcosm was carried out to determine the major factors involved in the inhibition of Enterococcus faecalis in the presence of aqueous extract of Eucalyptus microcorys. The planktonic bacterial cells remained in various concentrations of the aqueous solution at light intensities which fluctuated between 0 and 3,000 lx and incubation periods which ranged from 3 to 24 hours. A hierarchisation of studied factors revealed that the aqueous extract concentration, followed by experimental temperature, light intensity and incubation duration influence the inhibition of E. faecalis cells, respectively, with a rate of 86.82%, 7.03%, 5.25% and 0.90%. The cell abundances dropped significantly at 1.5% (λ = 0.491 and F = 5.518) and 2% (λ = 0.568 and F = 4.055) concentrations coupled with 1,000, 2,000 and 3,000 lx. The highest light intensities and extract concentration produce the highest log removal values. The disinfectant properties of E. microcorys were evaluated by the Chick–Watson model. This Chick–Watson model so obtained varied between log (N/No) = −0.09 Ct and log (N/No) = −0.17 Ct for extract concentrations of 1, 1.5 and 2%. Aqueous extract of E. microcorys could be used for water disinfection.

ABSTRACT The relative importance of viral lysis and bacterivory as causes of bacterial mortality were estimated. A laboratory experiment was carried out to check the kind of control that viruses could exert over the bacterial assemblage in a non-steady-state situation. Virus-like particles (VLP) were determined by using three methods of counting (DAPI [4′,6-diamidino-2-phenylindole] staining, YOPRO staining, and transmission electron microscopy). Virus counts increased from the beginning until the end of the experiment. However, different methods produced significantly different results. DAPI-stained VLP yielded the lowest numbers, while YOPRO-stained VLP yielded the highest numbers. Bacteria reached the maximal abundance at 122 h (3 × 107 bacteria ml−1), after the peak of chlorophyll a (80 μg liter−1). Phototrophic nanoflagellates followed the same pattern as for chlorophylla. Heterotrophic nanoflagellates showed oscillations in abundance throughout the experiment. The specific bacterial growth rate increased until 168 h (2.6 day−1). The bacterivory rate reached the maximal value at 96 hours (0.9 day−1). Bacterial mortality due to viral infection was measured by using two approaches: measuring the percentage of visibly infected bacteria (%VIB) and measuring the viral decay rates (VDR), which were estimated with cyanide. The %VIB was always lower than 1% during the experiment. VDR were used to estimate viral production. Viral production increased 1 order of magnitude during the experiment (from 106 to 107 VLP ml−1h−1). The percentage of heterotrophic bacterial production consumed by bacterivores was higher than 60% during the first 4 days of the experiment; afterwards, this percentage was lower than 10%. The percentage of heterotrophic bacterial production lysed by viruses as assessed by the VDR reached the highest values at the beginning (100%) and at the end (50%) of the experiment. Comparing both sources of mortality at each stage of the bloom, bacterivory was found to be higher than viral lysis at days 2 and 4, and viral lysis was higher than bacterivory at days 7 and 9. A balance between bacterial losses and bacterial production was calculated for each sampling interval. At intervals of 0 to 2 and 2 to 4 days, viral lysis and bacterivory accounted for all the bacterial losses. At intervals of 4 to 7 and 7 to 9 days, bacterial losses were not balanced by the sources of mortality measured. At these time points, bacterial abundance was about 20 times higher than the expected value if viral lysis and bacterivory had been the only factors causing bacterial mortality. In conclusion, mortality caused by viruses can be more important than bacterivory under non-steady-state conditions.

Abstract. Temperature and moisture are primary environmental drivers of soil organic matter (SOM) decomposition, and the development of a better understanding fo their roles in this process through depth in soils is needed. The objective of this research is to independently assess the roles of temperature and moisture in driving heterotrophic soil respiration for shallow and deep soils in a temperate red spruce forest. Minimally disturbed soil cores from shallow (0–25 cm) and deep (25–50 cm) layers were extracted from a 20 yr old red spruce stand and were then transferred to a climate chamber where they were incubated for 3 months under constant and diurnal temperature regimes. Soils were subjected to different watering treatments representing a full range of water contents. Temperature, moisture, and CO2 surface flux were assessed daily for all soils and continuously on a subset of the microcosms. The results from this study indicate that shallow soils dominate the contribution to surface flux (90%) and respond more predictably to moisture than deep soils. An optimum moisture range of 0.15 to 0.60 water-filled pore space was observed for microbial SOM decomposition in shallow cores across which a relatively invariant temperature sensitivity was observed. For soil moisture conditions experienced by most field sites in this region, flux-temperature relationships alone can be used to reasonably estimate heterotrophic respiration, as in this range moisture does not alter flux, with the exception of rewetting events along the lower part of this optimal range. Outside this range, however, soil moisture determines SOM decomposition rates.

Mung bean residues stimulate the hatching of soybean cyst nematode (SCN). In our previous study, combined incorporation of mung bean residues and biochar into soil can be effective in suppression of the soybean cyst nematode (SCN), Heterodera glycines, in the upper layer soil. However, there are no data available as to whether such effects are transmissible, and could for example be manifest in subsoil zones where such incorporation is confined to topsoils, via water-based pathways. We evaluated the effects of leachate passage from a biochar-amended soil in an upper soil zone to a lower zone in a microcosm-based system, upon a range of physicochemical properties and density of SCN. Disturbed soil was filled in a total of 9 cylindrical cores with two layers. The upper layer (0–15 cm) was amended with biochar at rates equivalent to 0, 0.3% or 1.8%, with bulk density set at of 1.1 g cm−3. The lower layer (15–25 cm) without biochar amendment was compacted to 1.2 g cm−3. Mung beans were grown for two weeks and incorporated into the upper layer. Water was surface-applied to the cores 4, 6, and 8 weeks after mung bean incorporation. After 16 weeks, the upper and lower layer soils were separately collected and assayed. The presence of biochar in the upper layer reduced the abundance of free-living nematodes, mainly bacterivorous, but increased that of a predator genus Ecumenicus in this zone. In the lower layer of soil under a biochar-amended upper layer, available P and soluble cations were increased as were abundances of total nematodes including Ecumenicus, resulting in greater maturity index, basal and structure indices. Notably, SCN density was decreased in lower zones by more than 90% compared to zero-biochar controls. This demonstrates that the effects of biochar upon soil properties, including impacts on biota and plant pathogens, are transmissible.

Herein, the effects of the contents of emulsified asphalt, waterborne epoxy resin emulsion, and curing agent on the permeability, bond shear strength, water stability, and aging resistance of epoxy-emulsified asphalt were studied. A formulation of epoxy-emulsified asphalt as a fog-sealing adhesive material was recommended, and a comparison between the fabricated adhesive material and a traditional Chinese fog-sealing adhesive material was conducted to verify the technical performance of the new material. In addition, the strength formation mechanism of the epoxy-emulsified asphalt was revealed via microcosmic analysis. Results show that the curing agent content mainly affects the permeability of epoxy-emulsified asphalt, and the emulsified asphalt content significantly affects the bond shear strength, water stability, and aging resistance. Moreover, the ratio of waterborne epoxy resin emulsion to the curing agent (epoxy ratio) has a certain effect on the bond shear strength. In the recommended formulation (a high-permeability and high-bonding fog-sealing adhesive material, which can be referred to simply as HPBFA), emulsified asphalt accounts for 80% of the total mass of the mixture, and the epoxy ratio is 2:1–3:1. It can improve air permeability, bond shear strength, water stability and aging resistance. The HPBFA-cured material exhibits a continuous three-dimensional network structure, hydrophobic surface, and large contact angle. Furthermore, the initial thermal weight loss temperature of the HPBFA-cured material is significantly higher than the environmental aging temperature. Additionally, the maximum temperature decomposition range is 0–160 °C, indicating improved strength, wear resistance, permeability, and aging resistance of the material.

The phytoremediation potential of aquatic plants, particularly for Cu, is scarcely reported in the pertinent literature. In this regard, differential growth behavior and phytoaccumulation ability of three free-floating Azolla species (A. japonica, A. pinnata, and A. hybrid) were evaluated in a climatically controlled (a temperature of 25/20 °C, light/dark 16/8 h, a light intensity of 60 µmol m−2 s−1, and a relative humidity of 65%) microcosm study. Azolla plants were exposed to solutions having three Cu concentrations (0, 3, and 6 mg L−1) under two incubation periods (4 and 8 days). Different Cu treatments significantly reduced Azolla biomass during both incubation periods and A. pinnata was the most sensitive species. Azolla plants grown in aqueous solutions showed substantial variations in Cu removal capacity. Higher bioconcentration values displayed by Azolla plants indicated that these plants can be deployed as potential plants for Cu removal from Cu contaminated water. Nevertheless, the plants exposed to higher Cu concentrations displayed color changes and root detachment due to Cu phytotoxic effects which may also ultimately lead to plant death. Significant correlations between Cu removed from the aqueous solutions and Cu contents of plant biomass indicated that Cu phytoremediation by Azolla plants was due to the phytoaccumulation mechanism because the removed Cu from aqueous solutions was accumulated in plant biomass. Introduced Azolla species, i.e., A. hybrid, displayed comparable Cu removal efficiency with naturally grown Azolla species, i.e., A. japonica and A. pinnata. Tested Azolla species proved to be suitable candidates to remediate Cu contaminated water and can be deployed for phytoremediation.

Biodegradation is a key process for the remediation of sites contaminated by petroleum hydrocarbons (PHCs), but this process is not well known for the (semi)-arid coastal environments where saline conditions and continuous water level fluctuations are common. This study differs from the limited previous studies on the biodegradation of PHCs in Qatari coastal soils mainly by its findings on the biodegradation kinetics of the selected PHCs of benzene and naphthalene by indigenous bacteria. Soil samples were collected above, across, and below the groundwater table at the eastern coast of Qatar within a depth of 0 to -40 cm. Environmental conditions combining low oxygen and high sulfate concentrations were considered in this study which could favor either or both aerobic and anaerobic bacteria including sulfate-reducing bacteria (SRB). The consideration of SRB was motivated by previously reported high sulfate concentrations in Qatari soil and groundwater. Low- and high-salinity conditions were applied in the experiments, and the results showed the sorption of the two PHCs on the soil samples. Sorption was dominant for naphthalene whereas the biodegradation process contributed the most for the removal of benzene from water. Losses of nitrate observed in the biodegradation experiments were attributed to the activity of nitrate-reducing bacteria (NRB). The results suggested that aerobic, NRB, and most likely SRB biodegraded the two PHCs, where the combined contribution of sorption and biodegradation in biotic microcosms led to considerable concentration losses of the two PHCs in the aqueous phase (31 to 58% after 21 to 35 days). Although benzene was degraded faster than naphthalene, the biodegradation of these two PHCs was in general very slow with rate coefficients in the order of 10-3 to 10-2 day-1 and the applied kinetic models fitted the experimental results very well. It is relevant to mention that these rate coefficients are the contribution from all the microbial groups in the soil and not from just one.

ABSTRACT Flooded rice fields have become a model system for the study of soil microbial ecology. In Italian rice fields, in particular, aspects from biogeochemistry to molecular ecology have been studied, but the impact of protistan grazing on the structure and function of the prokaryotic community has not been examined yet. We compared an untreated control soil with a γ-radiation-sterilized soil that had been reinoculated with a natural bacterial assemblage. In order to verify that the observed effects were due to protistan grazing and did not result from sterilization, we set up a third set of microcosms containing sterilized soil that had been reinoculated with natural assemblage bacteria plus protists. The spatial and temporal changes in the protistan and prokaryotic communities were examined by denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) analysis, respectively, both based on the small-subunit gene. Sequences retrieved from DGGE bands were preferentially affiliated with Cercozoa and other bacteriovorous flagellates. Without protists, the level of total DNA increased with incubation time, indicating that the level of the microbial biomass was elevated. Betaproteobacteria were preferentially preyed upon, while low-G+C-content gram-positive bacteria became more dominant under grazing pressure. The bacterial diversity detectable by T-RFLP analysis was greater in the presence of protists. The level of extractable NH4 + was lower and the level of extractable SO4 2− was higher without protists, indicating that nitrogen mineralization and SO4 2− reduction were stimulated by protists. Most of these effects were more obvious in the partially oxic surface layer (0 to 3 mm), but they could also be detected in the anoxic subsurface layer (10 to 13 mm). Our observations fit well into the overall framework developed for protistan grazing, but with some modifications pertinent to the wetland situation: O2 was a major control, and O2 availability may have limited directly and indirectly the development of protists. Although detectable in the lower anoxic layer, grazing effects were much more obvious in the partially oxic surface layer.

Nitrogen is a crucial nutrient for rice (Oryza sativa L.) productivity, and chemical N fertilizers are often applied to enhance rice production. However, the response of soil microbial activity and corresponding functional genes to chemical fertilization remains unclear. The present study was carried out during rainy (kharif) seasons of 2019 and 2020 at the research farms of ICAR-Indian Agricultural Research Institute, New Delhi to study in the microbial responses to different concentration of nitrogen and fertilizers applied to the soil of rice fields. Study included a microcosmic experiment with 3 N concentrations (0, 10, and 100 mM), and treatment included were T1, RDF; T2, 50% N as urea and KNO3 at 75:25 with PK; T3, 50% N as urea and KNO3 at 75:25 with PK and ammonium oxidizing microbial consortium. Nitrogen addition at 10 and 100 mM increased urease activity by 19–26%, potential ammonium oxidation (PAO) by 16–49%, and ureC gene copies by 10–22%. Indeed, treated soils possessed 1.2 to 6.5 folds’ higher copies of archaeal- and bacterial amoA. In the field experiments, the rhizosphere of T1 showed the highest urease and PAO activities while having the lowest activity of ammonification. The abundance of ureC, archaeal-, and bacterial amoA genes ranged from 2.9×106 to 2.0×107, 4.6×103 to 2.4×104, and 2.3 to 9.4×106 copies/g soil, respectively. The ureC gene copies were more abundant in T1, while archaeal and bacterial amoA genes exhibited the highest copies in T3. Urease activity and ureC copies were highest during the vegetative stage, while PAO, and archaeal- and bacterial amoA gene copies were enriched during the flowering stage. The gene abundance and associated enzymatic activities showed a strong correlation, implying that structural changes in the microbial community due to different combinations of fertilizers might alter the nutrient turnover in soil. Our results showed that N-fertilizers could significantly alter the structure and activities of microbial communities, and appropriate N fertilization is necessary for improving the sustainability of rice cultivation.

Abstract Abstract 3160 Recently, we reported that the neuropeptide, neuromedin U (NmU), functions as a novel extracellular cofactor with erythropoietin (EPO) to promote the expansion of early human erythroblasts. Because the expression of NmU is important during the early stages of erythropoiesis, we aimed to understand its temporal regulation during erythroid development. Although we have demonstrated that NmU is a target of the erythroid transcriptional regulator, c-Myb, our understanding of NmU regulation is incomplete. We hypothesized that microRNA (miRNA) molecules function to regulate NmU expression at the post-transcription level during erythropoiesis. Upon sequence analysis of the 3'-UTR of NmU using microCosm in the miRBase Targets database, 20 different miRNA molecules were predicted to interact with NmU's 3'-UTR. Among the 20 different miRNA molecules predicted to interact with NmU's 3'UTR, miR-101 was of interest, because in an independent study, its expression was elevated as measured by microarray analyses from primary human CD34+ cells cultured under erythroid inducing conditions. To determine the ability of miR-101 to directly interact with the 3'UTR of NmU, we used luciferase reporter assays. In a dose-dependent manner, miR-101 directly interacted with NmU's 3'-UTR. Also, 24-hours post-nucleofection of miR-101 into K562 cells, a hematopoietic cell line, the expression of NmU was decreased compared to control. Over-expression of miR-101 in primary human CD34+ cells decreased the growth of colony-forming unit-erythroid (CFU-E) ∼50% compared to control cells. In the presence of exogenously added NmU peptide, CFU-E growth from CD34+ cells over-expressing miR-101 was rescued to the level observed with control miRNA treated cells. To further determine the relationship between NmU, EPO, and miR-101, we cultured primary human CD34+ cells using a 2-phase liquid culture condition to induce erythroid development. During the first phase (days 0–6), the cells were cultured with IL-3, IL-6, and stem cell factor (SCF). The second phase of the erythroid inducing culture conditions began on day 6 when EPO was added to the culture. Erythroid differentiation was monitored using flow cytometry and fluorescent conjugated antibodies against CD34, transferrin receptor (CD71), and glycophorin A (GlyA). In parallel, primary cells were collected at regular intervals during culture to measure the expression of NmU mRNA and miR-101 by real time PCR (RT-PCR). Under our erythroid inducing culture conditions, NmU expression peaked between days 4 and 6 (before adding EPO) and between days 10 to 12. Also, between days 10 to 12 of culture in erythroid inducing conditions, we observed a dramatic increase in cell proliferation. Between days 13 to 15, cell proliferation reached a plateau, and the expression of miR-101 peaked. Erythroid progenitors purified from cord blood mononuclear cells by cell sorting revealed that NmU expression peaked in CD34-, CD71+, GlyA- (ERY2) cells, which is in good agreement with an independent microarray study, and miR-101 expression was not detected. By contrast, in CD34-, CD71lo, GlyA+ (ERY4) cells, miR-101 expression peaked while NmU expression decreased to the level observed in CD34-, CD71-, GlyA- cells. Combined, these data identify NmU as a novel miR-101 target and indicate that miR-101 regulates the temporal expression of NmU during the later stages of erythropoiesis. We hypothesize that the miR-101/NmU axis is a critical modulator of erythroid cell expansion that augments the effects of erythropoietin. Disclosures: Carroll: Glaxo Smith Kline, Inc.: Research Funding; Sanofi Aventis Corporation: Research Funding; TetraLogic Pharmaceuticals: Research Funding; Agios Pharmaceuticals: Research Funding.

Distance is the Quanta in E-Geometry, while Material-point is the Quanta in Physics and Material Geometry which is the Composition of Opposites and the Elements in Chemistry and Physics. As in Algebra Zero,0, is the Master-key number for all Positive and Negative numbers, and this because their sum and multiplication become zero, and the same on any coordinate-System where, ±, axes pass from zero, the Rolling of Positive ⊕ constituent on the Negative ⊝, constituent, creates the Neutral Material Point Which Equilibrium. Its Angular momentum B̅ is identical to the Spin S̅ and consists the First-Discrete-Energy- monad which occupies, Discrete Value and Direction, in contradiction to the Point,which is Nothing, Dimensionless, and without any Direction.Quaternion [(+)↻↺(-)] ≡ Box BQ ≡ Material Point ≡ Dipole, carries the Principal stress σ between A(+), B(-), which σ, as Centripetal-acceleration is the minimum Energy which becomes from the in Storage AB acceleration and is equal to the Gravity g. Because in-Box may exist different motions Revolving R and Periodic,P, the acceleration of Gravity g ≡  σ exists for the First Box-BR , while for the Second Box- BP is following the Local-Extreme-case where the acceleration of Gravity g ≡  σ, is the Locally altering Spin by changing the Principal-stress σ with an Local- uniform Pressure g L ≡ g kE = g * [Force/Area] = G, i.e. is proved that the minimum Local - Energy acceleration is the known Universal Gravitational-constant G = g k = kE g = kL σ = g. gL kL ≡σ.Φ3≡Φ[{σ Φ}≡[ 2B πr3 ]≡2πfP r ≡ v̅ ≡ mg = c̅ = 2.B πr3 ] such for Macrocosm and as for Microcosm, and Obeying Newton`s Laws of motion. Photon is a Box BR ≡ {It is the moving Energy-Storage, r, with The Golden ratio frequencies → fn = [ nσ 8 π2r 3 ]. B̅ ≡ (1+√5 ).σ 4πr = E h }, Transported with Light velocity by An Electromagnetic-Radiation of wavelength λ = c / fn= c / f1. It was Proved that Force G pressing, through Stress, g, to Enter the Critical-cave Lp in Planck-length with minimum Energy creates the Hydrogen - cave, while vibration fn , into the Energy – Space - Unit-meters, g, π, creates the Electron, e, and Charges, q̅. General Relativity touches the Planck - length while Quantum Mechanics begun to Penetrate in it. EPR Argument is a Void after the elucidating of the Geometry that is followed.as the Energy analysis the critic on the Fundamental Forces, the what is Energy- Quantization and what is Space-Energy.

<strong>ABSTRACT</strong> Present study aims to analyze the arsenate bioaccumulation and antioxidant defense responses in fronds of terrestrial fern <em>Ampelopteris prolifera</em> (Retz.) Copel and an aquatic fern <em>Azolla pinnata</em> R. Br. Both the ferns were exposed to increased concentrations of sodium arsenate (As; 0, 20, 60, 100, and 160 mg L^-1) with Hoagland nutrient solution. Shoot dry weight reduced in both ferns at 160 mg As L^-1 with higher decline in <em>A. pinnata</em> than <em>A. prolifera</em>. Fronds accumulated considerably higher As than roots but, compared to <em>A. pinnata</em>, <em>A. prolifera</em> transferred greater amount of As aboveground. Proper coordination among antioxidant defense facilitated high As accumulation in both ferns, but they differed in mechanistic responses. Reduced activities of ascorbate (AsA)-glutathione (GSH) cycle enzymes and increased level of &gamma;-glutamyl transpeptidases (&gamma;-GT) resulted in significant decline in GSH and AsA redox in <em>A. pinnata</em> at 160 mg As L^-1. Contrastingly, powered by increased antioxidant defense capacity and reduced level of &gamma;-GT, <em>A. prolifera</em> prevented As-induced oxidative damage. As triggered oxidative damage in <em>A. pinnata</em> through membrane lipid peroxidation and electrolyte leakage at 160 mg As L^-1. This consequently inhibited plant growth and As accumulation potential of the aquatic fern. <strong>Key words:</strong> <em>Ampeloptens prolifera, Azolla pinnata,</em> Aresenate, antioxidant, oxidative damage. <strong>REFERENCES</strong> Beyer, W.F. and Fridovich, I. 1987. Assaying for superoxide dismutase activity: some large consequences of minor changes in condition. Anal. Biochem. 161: 559-566. Bradford, M.M. 1976. 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Changes in elemental content in fronds of&nbsp;<em>Azolla filiculoides</em>&nbsp;due to arsenic accumulation. Plant Biosystems. in press. <strong>doi:</strong>10.1080/11263504.2015.1057257 Sarkar, A. and Jana, S. 1986. Heavy metal pollutant tolerance of <em>Azolla pinnata</em>. Water Air Soil pollut. 27: 15-18. Seelig, G.F. and Meister, A. 1984. &gamma;-Glutamylcysteine synthetase. J. Biol. Chem. 259: 3534-3538. Singh, A., Kumar, C.S. and Agarwal, A. 2013. Effect of lead and cadmium on aquatic plant <em>Hydrilla verticillata</em>. J. Environ. Biol. 34: 1027-1031. Singh, N. and Ma, L.Q. 2006. Arsenic speciation and arsenic and phosphate distribution in arsenic hyperaccumulator <em>Pteris vittata</em> L. and non-hyperaccumulator <em>Pteris ensiformis</em> L. Environ. Pollut. 141: 238&ndash;246. Singh, N., Ma, L.Q., Srivastava, M. and Rathinasabapathi, B. 2006. Metabolic adaptations to arsenic-induced oxidative stress in <em>Pteris vittata</em> L. and <em>Pteris ensiformis</em> L. Plant Sci. 170: 274&ndash;282. Singh, N., Raj, A., Khare, P.B., Tripathi, R.D. and Jamil, S. 2010. Arsenic accumulation pattern in 12 Indian ferns and assessing the potential of <em>Adiantum capillus-veneris</em>, in comparison to <em>Pteris vittata</em>, as arsenic hyperaccumulator. Bioresource Technol. 101: 8960&ndash;8968. Sood, A., Pabbi, S. and Uniyal, P.L. 2011. Effect of paraquat on lipid peroxidation and antioxidant enzymes in aquatic fern <em>Azolla microphylla</em> Kual. Russ. J. Plant Physiol. 58: 667-673. Sood, A., Uniyal, P.L., Prasanna, R. and Ahluwalia, A.S. 2014. Phytoremediation potential of aquatic macrophyte, <em>Azolla</em>. AMBIO. 41:122-137. Srivastava, M., Ma, L.Q., Singh, N. and Singh, S. 2005. Antioxidant responses of hyperaccumulator and sensitive fern species to arsenic. J. Exp. Bot. 56: 1335-1342. Srivastava, M., Santos, J., Srivastava, P. and Ma, L.Q. 2010. Comparison of arsenic accumulation in 18 fern species and four <em>Pteris vittata</em>. Bioresource Technol. 101: 2691&ndash;2699. Srivastava, S., Mishra, S., Tripathi, R.D., Dwivedi, S., Trivedi, P.K. and Tandon, P.K. 2007. Phytochelatins and antioxidant systems respond differentially during arsenite and arsenate stress in <em>Hydrilla verticillata </em>(L.f.) Royle. Environ. Sci. Technol. 41: 2930-2936. Sufian, J., Golchin, A., Avanes, A. and Moradi, S. 2013.&nbsp; Potentials of Azolla (<em>Azolla caroliniana</em>) for uptake of Arsenic from contaminated waters with different levels of salinity. Intl. J. Agri. Crop Sci. 6: 778-783. &nbsp; Swapna Gurrapu and Estari Mamidala. In Vitro HIV-1 Reverse Transcriptase Inhibition By Alkaloids Isolated From Leaves Of Eclipta Alba.. International Research Journal of Pharmacy. 2018, 9 (1). 66-70. DOI: 10.7897/2230-8407.09110. Talukdar, D. 2012. Ascorbate deficient semi-dwarf <em>asfL1 </em>mutant of <em>Lathyrus sativus </em>exhibits alterations in antioxidant defense. Biol. Plant. 56: 675-682. Talukdar, D. 2013a. Arsenic-induced oxidative stress in the common bean legume, <em>Phaseolus vulgaris</em> L. seedlings and its amelioration by exogenous nitric oxide. Physiol. Mol. Biol. Plants. 19: 69-79. Talukdar, D. 2013b. Plant growth and leaf antioxidant metabolism of four elite grass pea <em>(Lathyrus sativus</em>) genotypes, differing in arsenic tolerance. Agric. Res. 2: 330-339. Talukdar, D. 2013c. Floristic compositions and diversity of weed taxa in lentil (<em>Lens culinnaris&nbsp;</em>Medik.) fields. Bull.&nbsp; Env. Pharmacol. Life Sci. 2: 33-39. Talukdar, D. 2014. A common bean (<em>Phaseolus vulgaris</em>) mutant with constitutively low cysteine desulfhydrase activity exhibits growth inhibition but uniquely shows tolerance to arsenate stress. Environ. Exp. Biol. 12: 73-81. Talukdar, D. 2015. Functional interplay between glutathione and hydrogen sulfide in regulation of thiol cascade during arsenate tolerance of common bean (<em>Phaseolus vulgaris</em> L.) genotypes. 3 Biotech. 5: 819-829. Talukdar, D. and Talukdar, T. 2014. Coordinated response of sulfate transport, cysteine biosynthesis and glutathione-mediated antioxidant defense in lentil (<em>Lens culinaris</em> Medik.) genotypes exposed to arsenic. Protoplasma. 251:839&ndash;855. Talukdar, T. and Talukdar, D. 2015. Heavy metal accumulation as phytoremediation potential of aquatic macrophyte, <em>Monochoria vaginalis</em> (Burm. F.) K. Presl ex. kunth. Int. J. Appl. Sci. Biotechnol. 3: 9-15. Tripathi, P., Tripathi, R.D., Singh, R.P., Dwivedi, S., Chakrabarty, D., Trivedi, P.K. and Adhikari, B. 2013. Arsenite tolerance in rice (<em>Oryza sativa</em>L.) involves coordinated role of metabolic pathways of thiols and amino acids. Environ. Sci. Pollut. Res. 20: 884-896. Tu, C. and Ma, L.Q. 2005. Effects of arsenic on concentration and distribution of nutrients in the fronds of the arsenic hyperaccumulator <em>Pteris vittata</em> L. Environ. Pollut. 135: 333-340. Veljovic-Jovanovic, S.D., Pignocchi, C., Noctor, G. and Foyer, C.H. 2001. Low ascorbic acid in the <em>vtc-1 </em>mutant of <em>Arabidopsis</em> is associated with decreased growth and intracellular redistribution of the antioxidant system.&nbsp; Plant Physiol. 127: 426-435. Wang, C.Q., Chen, M. and Wang, B.S. 2007. Betacyanin accumulation in the leaves of C3 halophyte <em>Suaeda salsa</em> L. is induced by watering roots with H₂O₂. Plant Sci. 172:1-7. Wang, H.B., Wong, M.H., Lan, C.Y., Baker, A.J.M., Qin, Y.R., Shu, W.S., Chen, G.Z. and Ye, Z.H. 2007. Uptake and accumulation of arsenic by 11 <em>Pteris</em> taxa from southern China. Environ. Pollut. 145: 225-233. Zhang, X., Lin, A.J., Zhao, F.J., Xu,, G.Z., Duan, G.L. and Zhu, Y.G. 2008. Arsenic accumulation by the aquatic fern <em>Azolla</em>: Comparison of arsenate uptake, speciation and efflux by <em>Azolla caroliniana</em> and <em>Azolla filiculoides</em>. Environ. Pollut. 156: 1149&ndash;1155. Zhao, F.J., Ma, J.F., Meharg, A.A. and McGrath, S.P. 2009. Arsenic uptake and metabolism in plants. New Phytol. 181: 777&ndash;794.

Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants due to improper utilization in past industrial activity. Anaerobic reductive dechlorination, where bacteria use CAHs as electron acceptors, is crucial for bioremediation. Environmental conditions, such as nutrient availability and electron donors (i.e., molecular hydrogen), can influence the effectiveness of bioremediation processes. Also, bioremediation strategies like bioaugmentation (i.e., the supply of the enriched dechlorinating consortium) and bio-stimulation (i.e., the supply of electron donor) can improve CAHs removal performances. Here, a microcosm study is presented to assess the effectiveness of bioaugmentation with an enriched dechlorinating consortium for groundwater remediation. Target contaminants used were tetrachloroethane (TeCA), trichloroethylene (TCE) and sulphate ion. Various conditions, including biostimulation and bioaugmentation approaches were tested to evaluate the feasibility of biological treatment. Operating conditions, i.e., mineral medium and lactate, facilitated the dechlorination of TCE into ETH, leading to an increase in the dechlorinating population (Dehalococcoides mccartyi) to 67% of the total bacteria, with reductive dechlorination (RD) rates up to 7 µeq/Ld. Conversely, the RD performance of microcosms with real contaminated groundwater was negatively affected by the combined presence of TeCA and sulphate, indicated by a low abundance of D. mccartyi (&amp;lt;3%) and low RD rates (up to 0.39 µeq/Ld), suggesting that the native microbial population lacked the capacity for effective dechlorination. Moreover, the principal component analysis plot highlighted distinct groupings based on microbial community across different microcosm conditions, indeed, microbial community structures dominated by D. McCarty were associated with higher reductive dechlorination rates while non-augmented and non-stimulated microcosms reflected distinct microbial communities dominated by non-dechlorinating taxa. Additionally, RD decreased (48, 23, 22, and 14 µeq/Ld) with increasing sulphate concentrations (0, 150, 225, and 450 mgSO4 -2/L), further demonstrating the inhibitory effect of sulphate in the treated contaminated groundwater. Overall, this study highlights the complex interplay between environmental conditions, treatment strategies, and microbial communities in driving dechlorination processes. Specifically, the effectiveness of reductive dechlorination is heavily influenced by the availability of electron donors and the composition of the medium or groundwater, which can drive significant shifts in microbial community dynamics, either supporting or hindering the reductive dechlorination process.

ABSTRACT Acetate, propionate, and butyrate (volatile fatty acids [VFA]) occur in oil field waters and are frequently used for microbial growth of oil field consortia. We determined the kinetics of use of these VFA components (3 mM each) by an anaerobic oil field consortium in microcosms containing 2 mM sulfate and 0, 4, 6, 8, or 13 mM nitrate. Nitrate was reduced first, with a preference for acetate and propionate. Sulfate reduction then proceeded with propionate (but not butyrate) as the electron donor, whereas the fermentation of butyrate (but not propionate) was associated with methanogenesis. Microbial community analyses indicated that Paracoccus and Thauera (Paracoccus-Thauera), Desulfobulbus, and Syntrophomonas-Methanobacterium were the dominant taxa whose members catalyzed these three processes. Most-probable-number assays showed the presence of up to 107/ml of propionate-oxidizing sulfate-reducing bacteria (SRB) in waters from the Medicine Hat Glauconitic C field. Bioreactors with the same concentrations of sulfate and VFA responded similarly to increasing concentrations of injected nitrate as observed in the microcosms: sulfide formation was prevented by adding approximately 80% of the nitrate dose needed to completely oxidize VFA to CO2 in both. Thus, this work has demonstrated that simple time-dependent observations of the use of acetate, propionate, and butyrate for nitrate reduction, sulfate reduction, and methanogenesis in microcosms are a good proxy for these processes in bioreactors, monitoring of which is more complex. IMPORTANCE Oil field volatile fatty acids acetate, propionate, and butyrate were specifically used for nitrate reduction, sulfate reduction, and methanogenic fermentation. Time-dependent analyses of microcosms served as a good proxy for these processes in a bioreactor, mimicking a sulfide-producing (souring) oil reservoir: 80% of the nitrate dose required to oxidize volatile fatty acids to CO2 was needed to prevent souring in both. Our data also suggest that propionate is a good substrate to enumerate oil field SRB.

AbstractManaging and engineering microbial communities relies on the ability to predict their composition. While progress has been made on predicting compositions on short, ecological timescales, there is still little work aimed at predicting compositions on evolutionary timescales. Therefore, it is still unknown for how long communities typically remain stable after reaching ecological equilibrium, and how repeatable and predictable are changes when they occur. Here, we address this knowledge gap by tracking the composition of 87 two- and three-species bacterial communities, with 3–18 replicates each, for ~400 generations. We find that community composition typically changed during evolution, but that the composition of replicate communities remained similar. Furthermore, these changes were predictable in a bottom-up approach—changes in the composition of trios were consistent with those that occurred in pairs during coevolution. Our results demonstrate that simple assembly rules can hold even on evolutionary timescales, suggesting it may be possible to forecast the evolution of microbial communities.

AbstractThe electronic nose (E-nose) is a sensing technology that has been widely used to monitor environments in the last decade. In the present study, the capability of an E-nose, in combination with biochemical and microbiological techniques, of both detecting the microbial activity and estimating the metabolic status of soil ecosystems, was tested by measuring on one side respiration, enzyme activities and growth of bacteria in natural but simplified soil ecosystems over 23 days of incubation through traditional methodologies, and on the other side VOCs and/or gases evolution in their headspace during the same period through the E-nose. Both kinds of measurements, i.e. biochemical-microbiological and sensorial, succeeded in discriminating between inoculated and non-inoculated microcosms and in distinguishing different phases of bacterial growth and activity during the incubation. E-nose responses were highly and significantly correlated with all catalytic activities, respiration and different phases of bacterial growth. Hence, the E-nose was proved able to detect microbial activity in natural soil ecosystems. The metabolic status of these soil ecosystems was calculated on the base of some of the parameters previously tested in order to obtain a metabolic index (MI), ranging between 0 and 1. These MIs were then grouped into 3 classes, corresponding to a low, medium and high metabolic status. All the other measures were used as a multi-type data set in a partial least square discriminant analysis to generate a model capable of classifying the soil microcosms at different sampling dates according to the 3 classes of MIs. The resulting outcomes confirmed that the E-nose technology combined with both metabolic and biomass parameters can altogether represent reliable indicators of the metabolic status of soil ecosystems.

Abstract High-affinity H2-oxidizing bacteria (HA-HOB) thriving in soil are responsible for the most important sink of atmospheric H2. Their activity increases with soil organic carbon content, but the incidence of different carbohydrate fractions on the process has received little attention. Here we tested the hypothesis that carbon amendments impact HA-HOB activity and diversity differentially depending on their recalcitrance and their concentration. Carbon sources (sucrose, starch, cellulose) and application doses (0, 0.1, 1, 3, 5% Ceq soildw−1) were manipulated in soil microcosms. Only 0.1% Ceq soildw−1 cellulose treatment stimulated the HA-HOB activity. Sucrose amendments induced the most significant changes, with an abatement of 50% activity at 1% Ceq soildw−1. This was accompanied with a loss of bacterial and fungal alpha diversity and a reduction of high-affinity group 1 h/5 [NiFe]-hydrogenase gene (hhyL) abundance. A quantitative classification framework was elaborated to assign carbon preference traits to 16S rRNA gene, ITS and hhyL genotypes. The response was uneven at the taxonomic level, making carbon preference a difficult trait to predict. Overall, the results suggest that HA-HOB activity is more susceptible to be stimulated by low doses of recalcitrant carbon, while labile carbon-rich environment is an unfavorable niche for HA-HOB, inducing catabolic repression of hydrogenase.

Disposal in a geological disposal facility (GDF) is the preferred route for the world’s growing inventory of nuclear wastes. Bentonite clay is a common component of the engineered barrier system, serving to isolate and stabilise the high heat-generating waste packages in the geosphere (Stroes-Gascoyne et al. 2010). Bentonites naturally contain sulfate-reducing bacteria (SRB) (Haynes et al. 2021), which in the presence of the correct substrates, produce H2S that is highly corrosive to metals (such as steel waste packages). Sulfate, the electron acceptor, is present in most groundwaters, and the corrosion of steel produces hydrogen, an electron donor (Bagnoud et al. 2016). Compacting bentonite on deposition can restrict GDF microbial activity, since swelling pressures upon saturation restrict the available porosity for microbes (Masurat et al. 2010). Additionally, groundwater chemical conditions may impact bentonite mechanical properties (e.g., the effect of salinity on swelling capacity (He et al. 2019), and the energetics of bacterial metabolism (Oren 1999). This work uses bentonite SRB enrichment cultures to assess parameters that control microbial metabolism, and the relative contribution of microbially influenced corrosion (MIC), versus chemical corrosion of steel (Fig. 1). This will provide evidence to underpin lines of argument and models used in the safety assessments for geological disposal. Experiments described include microcosm incubations containing bentonite slurries across a range of salinity, and pressure cell bioreactors to evaluate the above conditions in the context of a compacted bentonite barrier system. Initial results show that in the presence of lactate as an electron donor, slurry systems with bentonite, low-carbon steel and sulfate-containing groundwater provide the essential nutrients for the proliferation of an MIC-inducing community (Fig. 2). Experiments have also shown that in such systems, increasing the groundwater NaCl concentration inhibits microbial activity during the 3-month experimental duration. Additionally, SRB have been shown to reduce priority radionuclides, such as selenium (Nancharaiah and Lens 2015). Selenium is a priority radionuclide in high-level waste, and in its highest oxidation states, selenate (Se(VI)) and selenite (Se(IV)), it is highly soluble and therefore mobile in the environment. Early experiments have shown that when an electron donor is present in microcosms containing bentonite and groundwater, bentonite-native SRB may be capable of reducing soluble selenium down to insoluble Se(0), restricting its environmental mobility.

This study applied genomic characterizations to a cocktail of three Salmonella enterica serovar Heidelberg (S. Heidelberg) strains different antimicrobial resistance (AMR) profile which were inoculated into fresh pine wood shavings (PWS) microcosms. The strains were isolated from feces (SH-AAFC), carcass (SH-ARS) and thigh (SH-FSIS) of broiler chicken. SH-AAFC harbored an antimicrobial resistant gene (ARG) blaCMY-2 on an IncI1 plasmid while SH-FSIS harbored multiple ARGs (floR, cmlA1, tet(A), blaTEM-1B, ant(2'')-Ia, aph(6)-Id, aph(3'')-Ib and sul2) on an IncC plasmid. SH-ARS was pan-susceptible. The die-off of Salmonella was determined at days 0, 1, 7, 14 and 21. Antibiotic susceptibility tests and whole genome sequencing were performed on 77 isolates. At 21 days post-inoculation, Salmonella abundance decreased by 4.4 Log10 CFU/g with the water activity of PWS being correlated with Salmonella survival. SH-AAFC clonal populations survived longer in PWS than SH-FSIS and SH-ARS populations. SH-AAFC clones persisting in litter carried higher copy number of Col plasmids than their ancestors, while some SH-ARS clones acquired a lysogenic bacteriophage from SH-FSIS populations. These results suggests that mobile genetic determinants such as plasmids (which could carry ARGs) and bacteriophage plays roles in the persistence of S. Heidelberg in the PWS used as broiler litter.

Saltmarsh is widely recognized as a blue carbon ecosystem with great carbon storage potential. Yet soil respiration with a major contributor of atmospheric CO2 can offset its carbon sink function. Up to date, mechanisms ruling CO2 emissions from saltmarsh soil remain unclear. In particular, the effect of precipitation on soil CO2 emissions is unclear in coastal wetlands, due the lack of outdoor data in real situations. We conducted a 7-year field manipulation experiment in a saltmarsh in the Yellow River Delta, China. Soil respiration in five treatments (−60%, −40%, +0%, +40%, and + 60% of precipitation) was measured in the field. Topsoils from the last 3 years (2019–2021) were analyzed for CO2 production potential by microcosm experiments. Furthermore, quality and quantity of soil organic carbon and microbial function were tested. Results show that only the moderate precipitation rise of +40% induced a 66.2% increase of CO2 production potential for the microcosm experiments, whereas other data showed a weak impact. Consistently, soil respiration was also found to be strongest at +40%. The CO2 production potential is positively correlated with soil organic carbon, including carbon quantity and quality. But microbial diversity did not show any positive response to precipitation sizes. r-/K-strategy seemed to be a plausible explanation for biological factors. Overall, our finding reveal that a moderate precipitation increase, not decrease or a robust increase, in a saltmarsh is likely to improve soil organic carbon quality and quantity, and bacterial oligotroph:copiotroph ratio, ultimately leading to an enhanced CO2 production.

Abstract All living organisms have theoretically an optimal stoichiometric nitrogen: phosphorus (N: P) ratio below and beyond which their growth is affected but data remain scarce for microbial decomposers. Here, we evaluated optimal N: P ratios of microbial communities involved in cellulose decomposition and assessed their stability when exposed to copper Cu(II). We hypothesized that (1) cellulose decomposition is maximized for an optimal N: P ratio, (2) copper exposure reduces cellulose decomposition and (3) increases microbial optimal N: P ratio, (4) N: P ratio and copper modify the structure of microbial decomposer communities. We measured cellulose disc decomposition by a natural inoculum in microcosms exposed to a gradient of N: P ratios at three copper concentrations (0, 1 and 15 µM). Bacteria were most probably the main decomposers. Without copper, cellulose decomposition was maximized at an N: P molar ratio of 4.7. Contrary to expectations, at high copper concentration, the optimal N: P ratio (2.8) and the range of N: P ratios allowing decomposition were significantly reduced and accompanied by a reduction of bacterial diversity. Copper contamination led to the development of tolerant taxa probably less efficient in decomposing cellulose. Our results shed new lights on the understanding of multiple stressor effects on microbial decomposition in an increasingly stoichiometrically imbalanced world.

Many studies have examined the survival of Escherichia coli and foodborne pathogens in agricultural soils. The results of these studies can be influenced by various growth conditions and growth media used when preparing cultures for an experiment. The objective of this study was to (i) determine the growth curves of rifampicin-resistant E. coli in three types of growth media containing rifampicin; tryptic soy agar (TSA-R), tryptic soy broth (TSB-R), and heat-treated poultry pellet extract (PPE-R), and (ii) evaluate the influence of growth media on the survival of E. coli in agricultural soil. Poultry pellet extract (PPE) was prepared by filter-sterilizing a 1:10 suspension of heat-treated poultry pellets in sterile water. Generic E. coli (TVS 353) acclimated to 80 µg/ml of rifampicin (R) was grown in TSA-R, TSB-R, and PPE-R at 3.0-3.5 log CFU/ml and at 37 °C. Growth curves were determined by quantifying E. coli populations at 0, 4, 8, 16, 24 and 32 h. Soil microcosms were inoculated with E. coli (6.0 log CFU/g) previously cultured in one of the three media types, stored at 25 °C, and soil samples were quantified for E. coli on days 0, 1, 3, 7, 14, 28 and 42. Growth curves and survival models were generated using DMFit and GInaFiT, respectively. E. coli growth rates were 0.88, 0.77, and 0.69 log CFU/ml/h in TSA-R, TSB-R, and PPE-R, respectively. E. coli populations in stationary phase were greater for cultures grown in TSA-R (9.4 log CFU/ml) and TSB-R (9.1 log CFU/ml) compared to PPE-R (7.9 log CFU/ml). The E. coli in the soil remained stable up to 3 d before declining. An approximate 2 log CFU/g decline of E. coli in soil was observed for each culture type between days 3 and 7, after which E. coli declined more slowly from day 7 to 42. A biphasic shoulder model was used to evaluate E. coli survival in soils based on growth media. Utilizing standardized culture growth preparation may aid in determining the complex interactions of enteric pathogen survival in soils.

IntroductionChanges in plant diversity and increased atmospheric nitrogen deposition independently influence soil nitrogen cycling in terrestrial ecosystems. However, the interactive effects of plant diversity and nitrogen deposition on soil nitrogen cycling multifunctionality (NCMF) in grassland ecosystems remain poorly understood.MethodsWe conducted a fully factorial microcosm experiment to quantify the responses and underlying mechanism of soil NCMF to nitrogen addition (0, 5, and 10 g N m−2 yr.−1) and plant diversity gradients (1, 3, and 6 species).ResultsOur results revealed a significant interactive effect between plant diversity and nitrogen addition on soil NCMF. Specifically, high plant diversity alleviated the negative effects of nitrogen addition on soil NCMF. The addition of nitrogen reduced the soil pH, which imposed microbial stress by limiting carbon availability. In contrast, higher plant diversity increased soil organic matter via below-ground carbon inputs, thereby reducing the soil carbon limitation of microorganims and enhancing the soil NCMF.DiscussionOverall, our findings suggest that maintaining or enhancing plant diversity in grasslands could be a key strategy to mitigate the adverse effects of atmospheric nitrogen deposition on soil nitrogen cycling, highlighting the crucial role of plant diversity in regulating ecosystem nutrient cycling under global change.

Climate change–induced temperature increase may influence the ecotoxicity of agricultural herbicides such as atrazine and consequently negatively impact aquatic biota. The objective of this study was to assess the effects of increased temperature on the ecotoxicity of atrazine to diatom community structure and stream periphyton load using laboratory microcosm experiments. A natural periphyton community from the Mukwadzi River, Zimbabwe, was inoculated into nine experimental systems containing clean glass substrates for periphyton colonisation. Communities were exposed to 0 µg∙L-1 (control), 15 µg∙L-1 and 200 µg∙L-1 atrazine concentrations at 3 temperature levels of 26°C, 28°C and 30°C. Periphyton dry weight and community taxonomic composition were analysed on samples collected after 1, 2 and 3 weeks of colonisation. A linear mixed-effects model was used to analyse the main and interactive effects of atrazine and temperature on dry mass, species diversity, evenness and richness. Temperature and atrazine had significant additive effects on species diversity, richness and dry mass. As temperature increased, diatom species composition shifted from heat-sensitive species such as Achnanthidium affine to heat-tolerant species such as Achnanthidium exiguum and Epithemia adnata. Increasing temperature in aquatic environments contaminated with atrazine results in sensitive and temperature-intolerant diatoms being eliminated from periphyton communities. Climate change will exacerbate effects of atrazine on periphyton dry mass and diatom community structure.

ABSTRACT STW 5, a blend of nine medicinal plant extracts, exhibits promising efficacy in treating functional gastrointestinal disorders, notably irritable bowel syndrome (IBS). Nonetheless, its effects on the gastrointestinal microbiome and the role of microbiota on the conversion of its constituents are still largely unexplored. This study employed an experimental ex vivo model to investigate STW 5’s differential effects on fecal microbial communities and metabolite production in samples from individuals with and without IBS. Using 560 fecal microcosms (IBS patients, n = 6; healthy controls, n = 10), we evaluated the influence of pre-digested STW 5 and controls on microbial and metabolite composition at time points 0, 0.5, 4, and 24 h. Our findings demonstrate the potential of this ex vivo platform to analyze herbal medicine turnover within 4 h with minimal microbiome shifts due to abiotic factors. While only minor taxonomic disparities were noted between IBS- and non-IBS samples and upon treatment with STW 5, rapid metabolic turnover of STW 5 components into specific degradation products, such as 18β-glycyrrhetinic acid, davidigenin, herniarin, 3-(3-hydroxyphenyl)propanoic acid, and 3-(2-hydroxy-4-methoxyphenyl)propanoic acid occurred. For davidigenin, 3-(3-hydroxyphenyl)propanoic acid and 18β-glycyrrhetinic acid, anti-inflammatory, cytoprotective, or spasmolytic activities have been previously described. Notably, the microbiome-driven metabolic transformation did not induce a global microbiome shift, and the detected metabolites were minimally linked to specific taxa. Observed biotransformations were independent of IBS diagnosis, suggesting potential benefits for IBS patients from biotransformation products of STW 5. IMPORTANCE STW 5 is an herbal medicinal product with proven clinical efficacy in the treatment of functional gastrointestinal disorders, like functional dyspepsia and irritable bowel syndrome (IBS). The effects of STW 5 on fecal microbial communities and metabolite production effects have been studied in an experimental model with fecal samples from individuals with and without IBS. While only minor taxonomic disparities were noted between IBS- and non-IBS samples and upon treatment with STW 5, rapid metabolic turnover of STW 5 components into specific degradation products with reported anti-inflammatory, cytoprotective, or spasmolytic activities was observed, which may be relevant for the pharmacological activity of STW 5.

Returning straw can alter the soil microbial community, reduce the occurrence of soilborne diseases, and promote plant growth. In this study, we aimed to evaluate the effects of Ricinus straw on tomato growth and rhizosphere microbial community. We carried out microcosm experiments to investigate the effects of Ricinus straw with different dosages (0, 1, and 3%) on tomato dry biomass and rhizosphere bacterial and fungal communities. The results indicated that the dry biomass of tomato seedlings with 1% addition of Ricinus straw increased by 53.98%. In addition, Ricinus straw also changed the abundance, diversities, and composition of tomato rhizosphere microbial communities. In detail, the addition of 1% Ricinus straw increased the relative abundance of putative beneficial bacteria and fungi in straw decomposition, such as Ramlibacter sp., Azohydromonas sp., Schizothecium sp., and Acaulium sp., and decreased the relative abundance of Fusarium sp. Meanwhile, Ricinus straw inhibited the growth of putative pathogenic microorganisms. The correlation analysis showed that the changes in fungal community operational taxonomic units stimulated by the addition of Ricinus straw may play a crucial positive regulatory role in tomato growth. Finally, the representative fungal strain Fusarium oxysporum f. sp. Lycopersici (FOL), named TF25, was isolated and cultured. We found that Ricinus straw extract inhibited the growth of TF25 in an in vitro experiment with an inhibition rate of 34.95–51.91%. Collectively, Ricinus straw promoted plant growth by changing the rhizosphere microbial community composition and inhibiting FOL growth, which provides new evidence for understanding the improvement of key microorganism composition in improving crop growth and the sustainability of agriculture.

Methane emissions from aquatic ecosystems are increasingly recognized as substantial, yet variable, contributions to global greenhouse gas emissions. This is in part due to the challenge of modeling biologic parameters that affect methane emissions from a wide range of sediments. For example, the impacts of fish bioturbation on methane emissions in the literature have been shown to result in a gradient of reduced to enhanced emissions from sediments. However, it is likely that variation in experimental fish density, and consequently the frequency of bioturbation by fish, impacts this outcome. To explore how the frequency of disturbance impacts the levels of methane emissions in our previous work we quantified greenhouse gas emissions in sediment microcosms treated with various frequencies of mechanical disturbance, analogous to different levels of activity in benthic feeding fish. Greenhouse gas emissions were largely driven by methane ebullition and were highest for the intermediate disturbance frequency (disturbance every 7 days). The lowest emissions were for the highest frequency treatment (3 days). This work investigated the corresponding impacts of disturbance treatments on the microbial communities associated with producing methane. In terms of total microbial community structure, no statistical difference was observed in the total community structure of any disturbance treatment (0, 3, 7, and 14 days) or sediment depth (1 and 3 cm) measured. Looking specifically at methanogenic Archaea however, a shift toward greater relative abundance of a putatively oxygen-tolerant methanogenic phylotype (ca. Methanothrix paradoxum) was observed for the highest frequency treatments and at depths impacted by disturbance (1 cm). Notably, quantitative analysis of ca. Methanothrix paradoxum demonstrated no change in abundance, suggesting disturbance negatively and preferentially impacted other methanogen populations, likely through oxygen exposure. This was further supported by a linear decrease in quantitative abundance of methanogens (assessed by qPCR of the mcrA gene), with increased disturbance frequency in bioturbated sediments (1 cm) as opposed to those below the zone of bioturbation (3 cm). However, total methane emissions were not simply a function of methanogen populations and were likely impacted by the residence time of methane in the lower frequency disturbance treatments. Low frequency mechanical disruption results in lower methane ebullition compared to higher frequency treatments, which in turn resulted in reduced overall methane release, likely through enhanced methanotrophic activities, though this could not be identified in this work. Overall, this work contributes to understanding how animal behavior may impact variation in greenhouse gas emissions and provides insight into how frequency of disturbance may impact emissions.