Silica Dynamics of Tidal Marshes in the Inner Elbe Estuary, Germany

In this study the seasonal and spatial variation of dissolved silica (DSi) and biogenic silica (BSi) in tidal marshes in the inner Elbe estuary was investigated. Seasonal sampling was conducted at three sites in the dyke foreland—the stretch of land between dyke and estuary—of the Elbe estuary, Germany. To assess the potential DSi export from the dyke foreland geographic information systems were used to calculate the DSi flux. Mean annual seepage DSi concentrations increased along the salinity gradient from 270 μmol L^???1 to 380 μmol L^???1. BSi concentration of the soil showed the opposite trend decreasing from 15.8 to 4.8 mg g^???1. Temporal variations of DSi concentrations were lowest at the freshwater site. At the brackish and saline site DSi concentrations increased about 2-fold from March to November from 200 to 500 and from 300 to 550 μmol L^???1, respectively. In March a diurnal signal of DSi uptake by diatoms could be observed at the saline sampling site, highlighting the role of sampling time and irradiance for the DSi flux estimate. DSi concentrations were reduced by 18.6 % between sunrise and noon. The DSi export from the dyke foreland is significant and equals the riverine DSi input into the estuary during times of low DSi concentrations. Furthermore the marsh DSi fluxes surpass DSi fluxes from highly active weathering regions, as reported in the literature, which corroborates the importance of tidal marsh areas for the coastal silica cycle. Factors steering the seasonality of DSi export and differences between the sites (temperature, hydrology, salinity and plant uptake of DSi) are discussed.     

Interface and border trap relaxation in Si–SiO2 structures with Ge nanocrystals examined by transient capacitance spectroscopy

The formation of interface and border states in metal–oxide–semiconductor structures associated with the generation of embedded germanium nanocrystals in 20 nm SiO₂-layers by means of ion implantation and a subsequent annealing was examined. Deep level transient spectroscopy and related time-domain techniques were applied in order to study the charge trapping and emission at the Si–SiO₂ interface. A significant dependence of the interface state density D_it on the conditions of the cluster generation was found. Any Ge-implanted sample features a pronounced level at about 0.31 eV above the valence band edge and a concentration above 10¹³ cm^?2 eV^?1, likely related to a P_b-center. A systematic variation of the filling pulse parameters was utilized in order to separate the response of fast and slow states, and to substantiate the existence of border traps located in the vicinity of the Si–SiO₂ interface. The role of interface and border traps for the relaxation of the trapped charge in the nanocrystals is illustrated.     

Secreted phosphoprotein 1 (osteopontin) is expressed by stromal macrophages in cyclic and pregnant endometrium of mice, but is induced by estrogen in luminal epithelium during conceptus attachment for implantation

Secreted phosphoprotein 1 (SPP1, osteopontin) is the most highly upregulated extracellular matrix/adhesion molecule/cytokine in the receptive phase human uterus, and Spp1 null mice manifest decreased pregnancy rates during mid-gestation as compared with wild-type counterparts. We hypothesize that Spp1 is required for proliferation, migration, survival, adhesion, and remodeling of cells at the conceptus-maternal interface. Our objective was to define the temporal/spatial distribution and steroid regulation of Spp1 in mouse uterus during estrous cycle and early gestation. In situ hybridization localized Spp1 to luminal epithelium (LE) and immune cells. LE expression was prominent at proestrus, decreased by estrus, and was nearly undetectable at diestrus. During pregnancy, Spp1 mRNA was not detected in LE until day 4.5 (day 1 = vaginal plug). Spp1-expressing immune cells were scattered within the endometrial stroma throughout the estrous cycle and early pregnancy. Immunoreactive Spp1 was prominent at the apical LE surface by day 4.5 of pregnancy and Spp1 protein was also co-localized with subsets of CD45-positive (leukocytes) and F4/80-positive (macrophages) cells. In ovariectomized mice, estrogen, but not progesterone, induced Spp1 mRNA, whereas estrogen plus progesterone did not induce Spp1 in LE. These results establish that estrogen regulates Spp1 in mouse LE and are the first to identify macrophages that produce Spp1 within the peri-implantation endometrium of any species. We suggest that Spp1 at the apical surface of LE provides a mechanism to bridge conceptus to LE during implantation, and that Spp1-positive macrophages within the stroma may be involved in uterine remodeling for conceptus invasion.     

Stimulus control of lingual predatory luring and related foraging tactics of mangrove saltmarsh snakes (nerodia clarkii compressicauda).

Knowledge of the various cues that elicit natural behavior is important to our understanding of why and when animals behave as they do. In order to gain insight into the behavior and ecology of Nerodia clarkii compressicauda, a piscivorous snake that uses a unique form of predatory luring as a foraging tactic, we observed 22 juvenile subjects in the presence of visual and chemical prey stimuli in a repeated-measures design. The use of video playback as a visual stimulus in this experiment permitted complete isolation from tactile and chemical cues. Snakes were more sedentary and used lingual luring more when both cue types were present than when none or only one of the cues was available. Subjects also attacked more often in the presence of both stimuli. Predatory attacks by prey-na?ve subjects directed to video cues when only visual prey stimuli were available demonstrated that snakes can identify prey visually without prior experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Witmer on comparative psychology.

Comments on P. McReynolds's (see record 1988-03153-001) discussion of L. Witmer's role in clinical psychology, noting that Witmer (1909, 1910) also made contributions to comparative psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dietary n−3 PUFA alter colonocyte mitochondrial membrane composition and function

There is experimental evidence that dietary fish oil, which contains the n−3 fatty acid family, i.e., EPA and DHA, protects against colon tumor development, in part by increasing apoptosis. Since mitochondria can act as central executioners of apoptosis, we hypothesized that EPA and DHA incorporation into colonocyte mitochondrial membranes, owing to their high degree of unsaturation, would enhance susceptibility to damage by reactive oxygen species (ROS) generated via oxidative phosphorylation. This, in turn, would compromise mitochondrial function, thereby initiating apoptosis. To test this hypothesis, colonic crypts were isolated from rats fed either fish oil, purified n−3 fatty acid ethyl esters, or corn oil (control). Dietary lipid source had no effect on colonic mitochondrial phospholipid class mole percentages, although incorporation of EPA and DHA was associated with a reduction in n−6 fatty acids known to enhance colon tumor development, i.e., linoleic acid (LNA) and its metabolic product, arachidonic acid (ARA). Select compositional changes in major phospholipid pools were correlated to alterations in mitochondrial function as assessed by confocal microscopy. The mol% sum of LNA plus ARA in cardiolipin was inversely correlated with ROS (P=0.024). Ethanolamine glycerophospholipid ARA (P=0.046) and choline glycerophospholipid INA (P=0.033) levels were positively correlated to mitochondrial membrane potential. In contrast, ethanolamine glycerophospholipid EPA (P=0.042) and DHA (P=0.024), levels were negatively correlated to mitochondrial membrane potential. Additionally, EPA and DHA levels in choline glycerophospholipids (P=0.026) were positively correlated with caspase 3 activity. These data provide evidence in vivo indicating that dietary FPA and DHA induce compositional changes in colonic mitochondrial membrane phospholipids that facilitate appotosis.     

Species and sex differences in substrate preference and tongue flick rate in three sympatric species of water snakes (Nerodia).

Tested isolation-reared sympatric water snakes (Nerodia r. rhombifera, N. c. cyclopion, and N. fasciata confluens) in a balanced 2-choice design to determine preference between clean and same-sex conspecific-soiled gravel substrates. Ss included 8 snakes (4 of each sex) of each species. Time spent on each substrate, types of tongue flicking behavior, tail vibration, defecation, and head rubbing were recorded. Species and sex differences were found in the relative time spent on the 2 substrates. Both sexes of N. rhombifera preferred the clean substrate, whereas both sexes of N. cyclopion preferred the soiled substrate, although the difference in time spent on the substrates was small for males. N. fasciata sexes differed in their preference, with the females preferring the soiled substrate and the males preferring, but not so strongly, the clean substrate. The frequencies of the 4 types of tongue extensions differed across species and sexes, with "air" tongue flicks accounting for the most variance. A lower total rate of tongue flicking occurred when the snakes were on the preferred substrate. These species and sex differences may help minimize competition due to dietary overlap between N. rhombifera and N. cyclopion, and between male and female N. fasciata. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Protein Expression of AEBP1, MCM4, and FABP4 Differentiate Osteogenic,Adipogenic, and Mesenchymal Stromal Stem Cells

Mesenchymal stem cells (MSCs) gain an increasing focus in the field of regenerative medicine due to their differentiation abilities into chondrocytes, adipocytes, and osteoblastic cells. However, it is apparent that the transformation processes are extremely complex and cause cellular heterogeneity. The study aimed to characterize differences between MSCs and cells after adipogenic (AD) or osteoblastic (OB) differentiation at the proteome level. Comparative proteomic profiling was performed using tandem mass spectrometry in data-independent acquisition mode. Proteins were quantified by deep neural networks in library-free mode and correlated to the Molecular Signature Database (MSigDB) hallmark gene set collections for functional annotation. We analyzed 4108 proteins across all samples, which revealed a distinct clustering between MSCs and cell differentiation states. Protein expression profiling identified activation of the Peroxisome proliferator-activated receptors (PPARs) signaling pathway after AD. In addition, two distinct protein marker panels could be defined for osteoblastic and adipocytic cell lineages. Hereby, overexpression of AEBP1 and MCM4 for OB as well as of FABP4 for AD was detected as the most promising molecular markers. Combination of deep neural network and machine-learning algorithms with data-independent mass spectrometry distinguish MSCs and cell lineages after adipogenic or osteoblastic differentiation. We identified specific proteins as the molecular basis for bone formation, which could be used for regenerative medicine in the future.