Metabolic threshold and sulfide-buffering in diffusion controlled marine sediments impacted by continuous organic enrichment

The effects of organic enrichment on sediment biogeochemistry was studied in diffusion controlled sediment mesocosms, where labile organic matter (OM) (fish feed) pulses were added once a week to the sediment surface. Two types of sediments, differing mainly in content of reactive Fe, were used. The aim of this experiment was two-fold, (1) to evaluate the importance of Fe-driven sulfide buffering for sulfide accumulation in surface enriched sediments, and (2) to estimate the diagenetic capacity for degradation of labile OM near the sediment surface. The simulated OM loading rate of 375 mmol C m^?2 day^?1 led to a 5–6 times increase in CO₂-production and a 4–5 times increase in O₂-uptake. Sulfate reduction estimated by radiotracer experiments and CO₂-release was 105–131 mmol m^?2 day^?1, but accumulation of porewater sulfide was low in both sediment types. Instead 99% of sulfide was oxidized with O₂ at the sediment water interface in the low Fe treatment, whereas 46% of produced sulfide precipitated as Fe-S compound in the high Fe treatment resulting in significantly lower O₂-uptake. Furthermore, the accumulation of up to 30% of added OM by the end of the experiment indicated a saturation of the heterotrophic microbial communities in the upper enriched surface layer. These results suggest a maximum diagenetic capacity for OM degradation in the range of ~25 μmol C cm^?3 day^?1 or 260 mmol m^?2 day^?1 for the present sediment types.     

Characterization of organic matter in cross-margin sediment transects of an upwelling region in the Campos Basin (SW Atlantic, Brazil) using lipid biomarkers

Lipid biomarkers [fatty acids (FAs), sterols and alcohols] and total organic carbon (TOC) were analyzed in 48 surface (0–2 cm) sediment samples collected twice (winter 2008/2009 and summer/2009) in two transects ranging from 25 to 3,000 m depths. This sampling array encompassed the major upwelling region in the southeastern Brazilian continental margin, where the river influence is probably minimal. The objectives were (1) to evaluate the sources, transport and major areas of organic matter (OM) accumulation in the continental margin and (2) to identify the fraction of OM that is potentially available to secondary benthic producers. As expected from the regional oceanographic characteristics, lipids derived from primary and secondary autochthonous producers (0.073–5.3 mg gTOC^?1) made the major fraction of the sedimentary OM, whereas lipids from allochthonous sources (0.043–0.40 mg gTOC^?1) and from bacteria (<0.01–0.43 mg gTOC^?1) were of relatively less importance. The accumulation of OM in the sediments was highly dependent on the coupling of physical (hydrodynamics) and biological (response to upwelling) factors. It was found that while some restricted areas in the shelf was a sink of labile OM, the export of this material to the upper and middle slope (400–1,000 m depths) can represent an important source of bioavailable OM to the deep sea benthic community.     

Biogeochemical processes at the sediment–water interface, Bombah Broadwater, Myall Lakes

Myall Lakes has experienced algal blooms in recent years which threaten water quality. Biomarkers, benthic fluxes measured with chambers, and pore water metabolites were used to identify the nature and reactivity of organic matter (OM) in the sediments of Bombah Broadwater (BB), and the processes controlling sediment-nutrient release into the overlying waters. The OM in the sediments was principally from algal sources although terrestrial OM was found near the Myall River. Terrestrial faecal matter was identified in muddy sediments and was probably sourced via runoff from farm lands. The reactive OM which released nutrients into the overlying waters was from diatoms, dinoflagellates and probably cyanobacteria. Microcystis filaments were observed in surface sediments. OM degradation rates varied between 5.3 and 47.1 mmol m^?2 day^?1 (64–565 mg m^?2 day^?1), were highest in the muddy sediments and sulphate reduction rates accounted for 20–40% of the OM degraded. Diatoms, being heavy sink rapidly, and are an important vector to transport catchment N and P to sites of denitrification and P-trapping in the sediments. Denitrification rates (mean ～4 mmol N m^?2 day^?1), up to 7 mmol N m^?2 day^?1 (105 mg N m^?2 day^?1) were measured, and denitrification efficiencies were highest (mean = 86 ± 4%) in the sandy sediments (～20% of the area of BB), but lower in the muddy sediments (mean = 63 ± 15%). These differences probably result from higher OM loads and anaerobic respiration in muddy sediments. Most DIP (>70%) from OM degradation was not released into overlying waters but remained trapped in surface sediments. Biophysical (advective) processes were responsible for the measured metabolite (O₂, CO₂, DSi, DIN and DIP) fluxes across the sediment–water interface.     

Depositional environment changes during the early–late Serravallian boundary dated by the Central Paratethys bioevents

The early–late Serravallian boundary (Badenian–Sarmatian) is a key interval for understanding Central Paratethys evolution. Environmental changes resulted in a great regional faunal turnover known as the Badenian-Sarmatian extinction event (BSEE). Here, we present a high-resolution sedimentological and biostratigraphical study from a rare site located on the Vienna and Danube basin junction (Slovakia). Four Middle Miocene depositional cycles/episodes ranked between 13.1 and 12.6 Ma are described in detail: (1) early Serravallian (13.1 Ma or older) shallow-marine episode; (2) early Serravallian (Badenian; Bulimina–Bolivina biozone; ~13.1 Ma or younger) outer shelf cycle; (3) late Serravallian (Sarmatian; large Elphidia biozone; ~12.6 Ma or younger) inner shelf cycle; (4) late Serravallian? A sedimentary episode represented by a scour filled with a reworked Serravallian (Upper Badenian and Sarmatian) material. The middle Miocene strata are overlaying and discordantly separated by Quaternary fluvial (floodplain) sediments (2.58 Ma or younger). These episodes reflect the early–late Serravallian turnover documented in the bioevents and in the sedimentological record.     

Influence of different fibre sources on digestibility and nitrogen and energy balances in growing pigs

Abstract

The present study was undertaken to investigate how three different fibre sources, sugar beet pulp, soya bean hulls and pectin residue, constituting 15% of diets for growing pigs, influenced daily body gain, feed conversion, apparent faecal digestibility and nitrogen and energy balances. Eight castrated crossbreed pigs (30 – 80 kg live weight) were used in a replicated 4 × 4 Latin-square design with one control diet and three fibre containing diets. Daily body weight gain and feed conversion were not affected by the dietary treatments. The apparent faecal digestibility of organic matter (OM) and energy were significantly lower for the fibre diets (OM: 0.81 – 0.85; energy: 0.78 – 0.83) compared to the control diet (OM: 0.88; energy: 0.86). The apparent faecal digestibility of crude protein (CP) was lower for the fibre diets (0.71 – 0.78) compared to the control diet (0.83), although it was only significantly lower for the sugar beet pulp and pectin residue diets. The pectin residue diet, which contained the highest amount of dietary fibre, lignin and insoluble non-starch polysaccharides, had the lowest digestibility of OM, CP and energy. There was a tendency (p = 0.07) for a diet effect on retained nitrogen in proportion to digested nitrogen, where the sugar beet pulp and pectin residue diets had numerically the highest values. Heat production and retained energy in proportion to metabolizable energy intake were not affected by fibre inclusion. It was concluded that the inclusion of sugar beet pulp, soya bean hulls and pectin residue in diets for growing pigs decreased the apparent faecal digestibility and in the diets with sugar beet pulp and pectin residue higher utilization of digested nitrogen for retention compensated for the lower amount of digested nitrogen.     

Type and branched pattern of N-glycans and their structural effect on the chicken egg allergen ovotransferrin: a comparison with ovomucoid

Ovotransferrin (OT), a multifunctional glycoprotein with defensive and protective activities, accounts for approximately 13 % of chicken egg white proteins and is known as a major egg-associated allergen along with ovomucoid (OM). In contrast to the well-characterized N-glycans of OM, the N-glycan structure of OT has not been reported. Here, using HPLC equipped with a fluorescence detector and mass spectrometric analysis in combination with exoglycosidase digestion, we investigated the N-glycan type and branched pattern of OT, and compared them with those of OM. The HPLC peak area was used to calculate the relative quantity (%) of each glycan. Seventeen N-glycans, including 11 glycans (1 core structure and 10 complex-type oligosaccharides), that commonly exist in ovotransferrin and ovomucoid were identified. Six characteristic glycans (2 truncated structures, 1 complex-type, and 3 hybrid-type oligosaccharides) in OT and eight characteristic glycans in OM were classified. OT contains the following branched complex-type structures: mono-(13.2 %), bi-(23.9 %), tri-(9.0 %), tetra-(2.7 %), and penta-(2.8 %) antennary oligosaccharides. However, OM contained mostly tri-(33.5 %) and penta-(31.2 %) antennary oligosaccharides. The N-glycan–containing bisecting N-acetylglucosamine comprised 43.4 % and 79.8 % of the total glycans in OT and OM, respectively. Moreover, using circular dichroism analysis, we observed that the secondary structure of the deglycosylated OT is quite different from that of the intact protein. To our knowledge, this is the first study to analyze N-glycans in OT in comparison with those of OM.     

Sequential density fractionation across soils of contrasting mineralogy: evidence for both microbial- and mineral-controlled soil organic matter stabilization

Sequential density fractionation separated soil particles into “light” predominantly mineral-free organic matter vs. increasingly “heavy” organo-mineral particles in four soils of widely differing mineralogy. With increasing particle density C concentration decreased, implying that the soil organic matter (OM) accumulations were thinner. With thinner accumulations we saw evidence for both an increase in ¹⁴C-based mean residence time (MRT) of the OM and a shift from plant to microbial origin.Evidence for the latter included: (1) a decrease in C/N, (2) a decrease in lignin phenols and an increase in their oxidation state, and (3) an increase in δ¹³C and δ¹⁵N. Although bulk-soil OM levels varied substantially across the four soils, trends in OM composition and MRT across the density fractions were similar. In the intermediate density fractions (~1.8–2.6 g cm^?3), most of the reactive sites available for interaction with organic molecules were provided by aluminosilicate clays, and OM characteristics were consistent with a layered mode of OM accumulation. With increasing density (lower OM loading) within this range, OM showed evidence of an increasingly microbial origin. We hypothesize that this microbially derived OM was young at the time of attachment to the mineral surfaces but that it persisted due to both binding with mineral surfaces and protection beneath layers of younger, less microbially processed C. As a result of these processes, the OM increased in MRT, oxidation state, and degree of microbial processing in the sequentially denser intermediate fractions. Thus mineral surface chemistry is assumed to play little role in determining OM composition in these intermediate fractions. As the separation density was increased beyond ~2.6 g cm^?3, mineralogy shifted markedly: aluminosilicate clays gave way first to light primary minerals including quartz, then at even higher densities to various Fe-bearing primary minerals. Correspondingly, we observed a marked drop in δ¹⁵N, a weaker decrease in extent of microbial processing of lignin phenols, and some evidence of a rise in C/N ratio. At the same time, however, ¹⁴C-based MRT time continued its increase. The increase in MRT, despite decreases in degree of microbial alteration, suggests that mineral surface composition (especially Fe concentration) plays a strong role in determining OM composition across these two densest fractions.     

Effects of land use on sources and ages of inorganic and organic carbon in temperate headwater streams

The amounts, sources and relative ages of inorganic and organic carbon pools were assessed in eight headwater streams draining watersheds dominated by either forest, pasture, cropland or urban development in the lower Chesapeake Bay region (Virginia, USA). Streams were sampled at baseflow conditions six different times over 1 year. The sources and ages of the carbon pools were characterized by isotopic (δ¹³C and ?¹⁴C) analyses and excitation emission matrix fluorescence with parallel factor analysis (EEM–PARAFAC). The findings from this study showed that human land use may alter aquatic carbon cycling in three primary ways. First, human land use affects the sources and ages of DIC by controlling different rates of weathering and erosion. Relative to dissolved inorganic carbon (DIC) in forested streams which originated primarily from respiration of young, ¹⁴C-enriched organic matter (OM; δ¹³C = ?22.2 ± 3 ‰; ?¹⁴C = 69 ± 14 ‰), DIC in urbanized streams was influenced more by sedimentary carbonate weathering (δ¹³C = ?12.4 ± 1 ‰; ?¹⁴C = ?270 ± 37 ‰) and one of pasture streams showed a greater influence from young soil carbonates (δ¹³C = ?5.7 ± 2.5 ‰; ?¹⁴C = 69 ‰). Second, human land use alters the proportions of terrestrial versus autochthonous/microbial sources of stream water OM. Fluorescence properties of dissolved OM (DOM) and the C:N of particulate OM (POM) suggested that streams draining human-altered watersheds contained greater relative contributions of DOM and POM from autochthonous/microbial sources than forested streams. Third, human land uses can mobilize geologically aged inorganic carbon and enable its participation in contemporary carbon cycling. Aged DOM (?¹⁴C = ?248 to ?202 ‰, equivalent¹⁴C ages of 1,811–2,284 years BP) and POM (?¹⁴C = ?90 to ?88 ‰, ¹⁴C ages of 669–887 years BP) were observed exclusively in urbanized streams, presumably a result of autotrophic fixation of aged DIC (?297 to ?244 ‰, ¹⁴C age = 2,251–2,833 years BP) from sedimentary shell dissolution and perhaps also watershed export of fossil fuel carbon. This study demonstrates that human land use may have significant impacts on the amounts, sources, ages and cycling of carbon in headwater streams and their associated watersheds.     

Fabrication of Nanosuspension Directly Loaded Fast-Dissolving Films for Enhanced Oral Bioavailability of Olmesartan Medoxomil: <Emphasis Type="Italic">In Vitro</Emphasis> Characterization and Pharmacokinetic Evaluation in Healthy Human Volunteers

Olmesartan medoxomil (OM) is an antihypertensive drug with poor water solubility and low oral bioavailability (28.6%). Accordingly, this study aimed to formulate and evaluate OM nanosuspension incorporated into oral fast-dissolving films (FDFs) for bioavailability enhancement. OM nanosuspension was prepared by antisolvent-precipitation-ultrasonication method and characterized regarding particle size (122.67?±?5.03 nm), span value (1.40?±?0.51), and zeta potential (??46.56?±?1.20 mV). Transmission electron microscopy (TEM) of the nanosuspension showed spherical non-aggregating nanoparticles. The nanosuspension was then directly loaded into FDFs by solvent casting technique. A full factorial design (2²?×?3¹) was implemented for optimization of the FDFs using Design-Expert® software. Physical and mechanical characteristics in addition to dissolution profiles of the FDFs were investigated. The optimum formula (FDF1) showed 0.43?±?0.02 kg/mm² tensile strength, 20.50?±?2.12 s disintegration time, and 87.53?±?2.50 and 95.99?±?0.25% OM dissolved after 6 and 10 min, respectively. Accelerated and long-term shelf stability studies confirmed the stability of FDF1. More than 75% OM was dissolved within 10 min from FDF1 compared with 9.80 and 47.80% for films prepared using coarse drug powder and market tablet, respectively. Relative bioavailability of FDF1 compared to market tablet was assessed in healthy human volunteers. The C_max value increased significantly from 66.62?±?14.95 to 179.28?±?23.96 ng/mL for market tablet and FDF1, respectively. Similarly, the AUC_0–72 value significantly increased from 498.36?±?217.46 to 1083.67?±?246.32 ng h/mL for market tablet and FDF1, respectively. Relative bioavailability of FDF1 was 209.28%. The highlighted results verified the effectiveness of OM nanosuspension-loaded FDFs in improving OM bioavailability.     

First report of rodents from the late Hemphillian (late Miocene) Zwiebel Channel and a revised late Neogene biostratigraphy/biochronology of the Sand Draw area of Nebraska

A new late Hemphillian (late Miocene) rodent assemblage is reported from Zwiebel Channel, a channel cut into underlying Ash Hollow Miocene sediments along Sand Draw, Brown County, Nebraska. This locality extends the temporal range of rodent history in the Sand Draw area. A new biostratigraphic hypothesis proposes that previously described assemblages with Ogmodontomys are older than those with Ophiomys, as is the case in the Meade Basin of southwestern Kansas. Consequently, two Pliocene temporal zones are recognised. Based on a phylogenetic analysis of Ophiomys, rodent biostratigraphy, and paleomagnetic profiles, Sand Draw assemblages with Ogmodontomys are considered to have been deposited about 3.0–2.8 Ma, while those with Ophiomys were laid down between about 2.8–2.5 Ma. The 1.6 Ma date previously suggested for Ophiomys parvus from Froman Ferry, Idaho is probably too young; it is more likely that O. parvus became extinct in Idaho prior to the North American Microtus immigration event at about 2.0 Ma, inhabiting the Snake River basin until around 2.2 Ma.     

Fluid–structure interactions in micro-interlocked regions of the cement–bone interface

Experimental tests and computational modelling were used to explore the fluid dynamics at the trabeculae–cement interlock regions found in the tibial component of total knee replacements. A cement–bone construct of the proximal tibia was created to simulate the immediate post-operative condition. Gap distributions along nine trabeculae–cement regions ranged from 0 to 50.4 μm (mean = 12 μm). Micro-motions ranged from 0.56 to 4.7 μm with a 1 MPa compressive load to the cement. Fluid–structure analysis between the trabeculae and the cement used idealised models with parametric evaluation of loading direction, gap closing fraction (GCF), gap thickness, loading frequency and fluid viscosity. The highest fluid shear stresses (926 Pa) along the trabecular surface were found for conditions with very thin and large GCFs, much larger than reported physiological levels (～1–5 Pa). A second fluid–structure model was created with a provision for bone resorption using a constitutive model with resorption velocity proportional to fluid shear rate. A lower cut-off was used, below which bone resorption would not occur (50 s^? 1). Results showed that there was initially high shear rates (>1000 s^? 1) that diminished after initial trabecular resorption. Resorption continued in high shear rate regions, resulting in a final shape with bone left deep in the cement layer, and is consistent with morphology found in post-mortem retrievals. Small gaps between the trabecular surface and the cement in the immediate post-operative state produce fluid flow conditions that appear to be supra-physiologic; these may cause fluid-induced lysis of trabeculae in the micro-interlock regions.     

Linking terrestrial and benthic estuarine ecosystems: organic matter sources supporting the high secondary production of a non-indigenous bivalve

The Asian clam, Corbicula fluminea, is among the most pervasive invasive species in freshwater ecosystems worldwide. Our objective was to study C. fluminea’s functional response in terms of feeding behavior and food selectivity, using the natural variation in organic matter (OM) sources that occur in estuarine environments. Using C and N stable isotopes, we identified and quantified the contribution of different OM sources supporting the production of C. fluminea along the salinity gradient occupied in the Minho River estuary (NW-Iberian Peninsula, Europe), where this species presently dominates the benthic macrofauna biomass. We observed a pronounced shift in the quality of OM available for C. fluminea along the estuarine mixing zone. Stable isotope analysis, POM C/N, and phytoplankton contribution estimates based on C:Chl a revealed that POM was largely comprised of terrestrial-derived OM in tidal freshwater stations (TFW) and was increasingly comprised of phytoplankton, a more palatable food source, towards the polyhaline estuary. A similar shift in the isotopic composition along the estuarine mixing zone was observed in C. fluminea, suggesting a shift in food resources. Accordingly, based on a Bayesian stable isotope mixing model, there was an upstream–downstream counter gradient in the contribution to C. fluminea biomass from terrestrial-derived OM (41–64 % in TFW) and phytoplankton (29–55 % in the brackish estuary). Although the majority of the food sources identified were filtered from the water column (70–80 %), reliance on sediment OM and microphytobenthos provided evidence for deposit feeding by C. fluminea. We conclude that C. fluminea has the ability to adapt to environments with low food quality because it can consume terrestrial-derived OM. This can be a competitive adaptation in systems with perennial low food quality such as the Minho River estuary. Moreover, its ability to couple benthic and pelagic environments and terrestrial ecosystems demonstrates a strong potential to alter food web flows in aquatic ecosystems.     

Evolutionary response of Caragana (Fabaceae) to Qinghai–Tibetan Plateau uplift and Asian interior aridification

Caragana is endemic to temperate Asia, with most species distributed on the Qinghai–Tibetan Plateau (QTP) and in Northwestern China. Consequently its biogeography should be hypothesized to have been affected by QTP uplift. To examine the biogeography of Caragana in relation to QTP uplift and consequent interior aridification, we conducted molecular dating analyses based on three genes (ITS, cpDNA trnS-trnG and rbcL). Results from relaxed Bayesian BEAST, relaxed Bayesian Multidivtime, and PL (penalized likelihood) indicate that QTP uplift, especially the onset of Himalayan motion at 21–17 Ma, triggered the origin of Caragana (with estimated ages 16–14 Ma). The subsequent QTP rapid uplift at 8 Ma is inferred to have driven the evolution and diversification of the three major clades of Caragana: section Caragana (northern China and the Junggar–Altai–Sayan region), section Frutescentes (Central Asia), and sections Bracteolatae and Jubatae, centered in the QTP. A rapid and active speciation process occurring in the QTP intense uplift at 3.4–1.8 Ma, is indicated by the chronogram.     

Melittin-Induced Permeabilization,Re-sealing,and Re-permeabilization of E. coli Membranes

The permeabilization of model lipid bilayers by cationic peptides has been studied extensively over decades, with the bee-sting toxin melittin perhaps serving as the canonical example. However, the relevance of these studies to the permeabilization of real bacterial membranes by antimicrobial peptides remains uncertain. Here, we employ single-cell fluorescence microscopy in a detailed study of the interactions of melittin with the outer membrane (OM) and the cytoplasmic membrane (CM) of live Escherichia coli. Using periplasmic green fluorescent protein (GFP) as a probe, we find that melittin at twice the minimum inhibitory concentration first induces abrupt cell shrinkage and permeabilization of the OM to GFP. Within ～4 s of OM permeabilization, the CM invaginates to form inward facing “periplasmic bubbles.” Seconds later the bubbles begin to leak periplasmic GFP into the cytoplasm. Permeabilization is localized, consistent with possible formation of toroidal pores. Within ～20 s, first the OM and then the CM re-seals to GFP. Some 2–20 min later, both CM and OM are re-permeabilized to GFP. We invoke a mechanism based on curvature stress concepts derived from model bilayer studies. The permeabilization and re-sealing events involve sequential, time-dependent build-up of melittin density within the outer and inner leaflets of each bilayer. We also propose a mechanical explanation for the early cell shrinkage event induced by melittin and a variety of other cationic peptides. As peptides gain access to the periplasm, they bind to the anionic peptido-crosslinks of the lipopolysaccharide layer, increasing its longitudinal elastic modulus. The cell wall shrinks because it can withstand the same turgor pressure with smaller overall extension. Shrinkage in turn induces invagination of the CM, preserving its surface area. We conclude by comparing the behavior of different peptides.     

Effect of niacin supplementation on digestibility,nitrogen utilisation and milk and blood variables in lactating dairy cows fed a diet with a negative rumen nitrogen balance

The aim of the present experiment was to determine if a niacin supplementation of 6 g/d to lactating dairy cow diets can compensate negative effects of a rumen nitrogen balance (RNB) deficit. A total of nine ruminally and duodenally fistulated lactating multiparous German Holstein cows were successively assigned to one of three diets consisting of 10 kg maize silage (dry matter [DM] basis) and7 kg DM concentrate: Diet RNB– (n = 6) with energy and utilisable crude protein at the duodenum (uCP) according to the average requirement of the animals but with a negative RNB (–0.41 g N/MJ metabolisable energy [ME]); Diet RNB0 (n = 7) with energy, uCP and a RNB (0.08 g N/MJ ME) according to the average requirement of the animals and, finally, Diet NA (n = 5), which was the same diet as RNB–, but supplemented with 6 g niacin/d. Samples of milk were taken on two consecutive days, blood samples were taken on one day pre- and post-feeding and faeces and urine were collected completely over five consecutive days. The negative RNB reduced milk and blood urea content and apparent total tract digestibility of DM, organic matter (OM) and neutral detergent fibre (NDF). Also N excretion with urine, the total N excreted with urine and faeces and the N balance were reduced when the RNB was negative. Supplementation of niacin elevated plasma glucose concentration after feeding and the N balance increased. Supplementing the diet with a negative RNB with niacin led to a more efficient use of dietary N thereby avoiding the negative effects of the negative RNB on the digestibility of DM, OM and NDF.     

Evaluation of cystatin C as an early biomarker of cadmium nephrotoxicity in the rat

Cadmium (Cd) is a nephrotoxic environmental pollutant that causes insidious injury to the proximal tubule that results in severe polyuria and proteinuria. Cystatin C is a low molecular weight protein that is being evaluated as a serum and urinary biomarker for various types of ischemic and nephrotoxic renal injury. The objective of the present study was to determine if cystatin C might be a useful early biomarker of Cd nephrotoxicity. Male Sprague–Dawley rats were given daily injections of Cd for up to 12 weeks. At 3, 6, 9 and 12 weeks, urine samples were analyzed for cystatin C, protein, creatinine, β₂ microglobulin and kidney injury molecule-1. The results showed that Cd caused a significant increase in the urinary excretion of cystatin C that occurred 3–4 weeks before the onset of polyuria and proteinuria. Serum levels of cystatin C were not altered by Cd. Immunolabeling studies showed that Cd caused the relocalization of cystatin C from the cytoplasm to the apical surface of the epithelial cells of the proximal tubule. The Cd-induced changes in cystatin C labelling paralleled those of the brush border transport protein, megalin, which has been implicated as a mediator of cystatin C uptake in the proximal tubule. These results indicate that Cd increases the urinary excretion of cystatin C, and they suggest that this effect may involve disruption of megalin-mediated uptake of cystatin C by epithelial cells of the proximal tubule.     

Biochronology of the first hominid remains in Europe using the vole Mimomys savini: Fuente Nueva 3 and Barranco León D,Guadix-Baza Basin,south-eastern Spain

The sites of Barranco León D (BL-D) and Fuente Nueva 3 (FN-3) in the Guadix-Baza Basin (Granada, Spain), together with the site of Sima del Elefante in the Sierra de Atapuerca (Burgos, Spain), constitute one of the oldest records of the earliest hominid population in the European continent west of Dmanisi (Georgia, Lesser Caucasus). In the Guadix-Baza Basin, evidence of human occupation has been found to date in the form of lithic industry (Mode 1) and cut marks in large-mammal fossil remains (mainly of hippopotamuses and elephants), and recently a human tooth considered as the oldest in Europe has been discovered. Although in the case of Sima del Elefante there is unanimity among the scientific community regarding the chronology of the unit in which the hominid remains were found (Unit TE9c, 1.22 Ma), there is continuing debate on the chronology of the sites of the Guadix-Baza Basin (FN-3 and BL-D). This applies especially to BL-D, as the numerical datings published for this site have a very high error range (1.4 ± 0.38 Ma). In this paper, the chronology of these two sites is determined using as a marker the morphological and morphometric changes undergone by Mimomys savini in its first lower molar (m1) over the course of its evolutionary history. It has been possible to confirm that the oldest human presence in the Guadix-Baza Basin and at Sima del Elefante (Atapuerca) share a similar chronology, dated to between 1.1 and 1.4 Ma. Apparently, the oldest site with human remains in Europe is seen to be BL-D, dated to 1.26 ± 0.13 Ma, followed by Level TE9c, dated to 1.22 ± 0.16 Ma, and FN-3, dated to 1.20 ± 0.12 Ma.     

Restored floodplains enhance denitrification compared to naturalized floodplains in agricultural streams

Predicted changes in the timing and magnitude of storms have the potential to amplify water quality challenges associated with agricultural runoff. In agricultural streams of the Midwestern US, floodplain restoration has the potential to enhance inorganic nitrogen (N) removal by increasing the bioreactive surface area for microbially-mediated denitrification. The restoration of inset floodplains via construction of the two-stage ditch increases denitrification compared to channelized systems, however, little is known about how denitrification on restored floodplains compares to those formed naturally when stream channel management lapses. We used sacrificial microcosm incubations and membrane-inlet mass spectrometry (MIMS) to compare denitrification rates in floodplain soils collected along transects in both naturalized and restored floodplains; longitudinal transects spanned two zones in the active floodplain (near-stream, NS vs. middle, MID) and a third zone that reflected upland conditions in the riparian buffer strip (UP). Denitrification rates were 35–49% higher in the restored, inset floodplains compared to naturalized floodplains. Variation in denitrification rates were primarily explained by soil organic matter (OM) and OM was > 20% higher in restored floodplains than naturalized, highlighting the contrasts between stable, constructed floodplains with heterogeneous, depositional bars typical of naturalizing channels. Consequently, restored inset floodplains could remove > 70% more N than the naturalized floodplains during similar storm inundation events.     

Phylogenomics,molecular evolution,and estimated ages of lineages from the deep phylogeny of Poaceae

The deeply diverging subfamilies of grasses: Anomochlooideae, Pharoideae, and Puelioideae, today inhabit tropical forest floors as sparsely distributed depauperate lineages. The BEP/PACMAD grasses, which make up the majority of the family, are the result of a more recent radiation. Species in the deeply diverging subfamilies were here investigated to better understand molecular evolutionary processes and ages of divergence. Complete chloroplast genomes (plastomes) of Pharus latifolius L., P. lappulaceus Aubl., and Puelia olyriformis (Franch.) Clayton were determined. Four plastome loci from seven species of the deep subfamilies were also sequenced. Phylogenetic and mutation analyses and divergence estimations were conducted on all sequences together with homologous sequences from other Poaceae. Mutation analyses surveyed insertion/deletion mutations across the plastomes, clarified a trend in the molecular evolution of the rpoC2 locus, and indicated unique pseudogenizations in the plastomes of Pharus and Puelia. Phylogenetic analyses largely confirmed earlier multi-gene phylogenies. Phylogenomic and divergence analyses produced estimated origins of the crown nodes of Anomochlooideae at 65–104 Ma, Pharoideae at 44–71 Ma, and Puelioideae at 62–96 Ma. The upper ends of our estimated ranges are in general agreement with previous estimates. However, the lower ends of our ranges are considerably older than previous estimates, reflecting the influence of the less commonly used oldest fossil calibration point. The deeply diverging subfamilies exhibited the accumulation of numerous substitution and indel mutations consistent with a long evolutionary history that predated the radiation of the BEP/PACMAD grasses. We hypothesize that relatively rapid warming and drying in Africa at 55–56.5 Ma may have acted as selective forces stimulating adaptive radiations of grasses from the African tropical forests into diverse habitats.     

Allochthonous Organic Matter Supports Benthic but Not Pelagic Food Webs in Shallow Coastal Ecosystems

Rivers transport large amounts of allochthonous organic matter (OM) to the ocean every year, but there are still fundamental gaps in how allochthonous OM is processed in the marine environment. Here, we estimated the relative contribution of allochthonous OM (allochthony) to the biomass of benthic and pelagic consumers in a shallow coastal ecosystem in the northern Baltic Sea. We used deuterium as a tracer of allochthony and assessed both temporal variation (monthly from May to August) and spatial variation (within and outside river plume). We found variability in allochthony in space and time and across species, with overall higher values for zoobenthos (26.2 ± 20.9%) than for zooplankton (0.8 ± 0.3%). Zooplankton allochthony was highest in May and very low during the other months, likely as a result of high inputs of allochthonous OM during the spring flood that fueled the pelagic food chain for a short period. In contrast, zoobenthos allochthony was only lower in June and remained high during the other months. Allochthony of zoobenthos was generally higher close to the river mouth than outside of the river plume, whereas it did not vary spatially for zooplankton. Last, zoobenthos allochthony was higher in deeper than in shallower areas, indicating that allochthonous OM might be more important when autochthonous resources are limited. Our results suggest that climate change predictions of increasing inputs of allochthonous OM to coastal ecosystems may affect basal energy sources supporting coastal food webs.