Parameterization of surface irradiance and primary production in Århus Bay,SW Kattegat,Baltic Sea

The aims of the present study were to develop a parameterization of a one-year-long observed PAR time-series, apply the PAR parameterization in a primary production relation, and compare calculated and observed time-series of primary production. The PAR parameterization was applied in the generally used relation for the primary production (P _d): P _d = a(BI ₀ Z ₀) + b with observed photic depth (Z ₀) and Chl-a concentrations (B). It was tested whether the PAR parameterization in combination with this simple relation for primary production was able to describe the actual measured primary production. The study is based on a one year long time-series of PAR, CTD-casts (n = 45), and primary production measurements (n = 24) from Århus Bay (56°09′ N; 10°20′ E), south west Kattegat. Results showed a high and positive correlation between observed and calculated primary production in the bay, as based on the present PAR parameterization combined with the simple primary production relation. The developed PAR parameterization, which calculates total daily surface irradiance per day (M photons m^?2 d^?1), can be applied in any ecological application taking into account that it was developed for the latitude of 56° N.     

Diversity of bacteria in surface ice of Austre Lovénbreen glacier, Svalbard

Two 16S rRNA gene clone libraries Cores 1U and 2U were constructed using two ice core samples collected from Austre Lovénbreen glacier in Svalbard. The two libraries yielded a total of 262 clones belonging to 59 phylotypes. Sequences fell into 10 major lineages of the domain Bacteria, including Proteobacteria (alpha, beta, gamma and delta subdivisions), Bacteroidetes, Actinobacteria, Firmicutes, Acidobacteria, Deinococcus-Thermus, Chloroflexi, Planctomycetes, Cyanobacteria and candidate division TM7. Among them, Bacteroidetes, Actinobacteria, Alphaproteobacteria and Cyanobacteria were most abundant. UniFrac data showed no significant differences in community composition between the two ice cores. A total of nineteen bacterial strains from the genera Pseudoalteromonas and Psychrobacter were isolated from the ice cores. Phylogenetic and phenotypic analyses revealed a close relationship between the ice core isolates and bacteria in marine environments, indicating a wide distribution of some bacterial phylotypes in both terrestrial and marine ecosystems.     

Breast-milk mercury concentrations and amalgam surface in mothers from Brasília, Brazil

Human milk is the best source of nourishment for the newborn because of its incomparable balanced nutrition and psychological benefits to the infant's development. Dental fillings containing metallic Hg are the primary source of inorganic Hg contamination of humans. We studied Hg concentrations in the breast milk of mothers during the first month (7-30 d) postnatal in relation to the number of amalgam surfaces. The concentration of total Hg was determined in 23 samples of human milk collected from lactating mothers with a varied number of amalgam dental restorations. The average number of amalgam surfaces was 6.87 (5.81, SD) with a range of 0 to 20. The mean concentration of total Hg in breast milk was 5.73 ng/g (range: 0-23.07). The Pearson correlation coefficient was significant (r = 0.6087, p = 0.0057) between breast-milk Hg and number of amalgam surfaces. In 56.5% of low-fish-eating mothers, the amount of Hg likely to be ingested by breast-fed infants is above the World Health Organization reference.     

Pollution,source, and ecological risk assessment of trace elements in surface sediments of Lake Aktaş, NE Turkey

This study applies ecological indices to determine the anthropogenic-based metal enrichment and potential ecological and ecotoxicological risks posed by each metal in the sediments of Lake Akta?, NE Turkey. Sediment samples were collected from nine stations (St1–St9) within the Turkish boundary of Lake Akta? and the heavy metal, total organic carbon %, CaCO₃%, chlorophyll degradation products (chlorophyll-α), total sulfur %, and total phosphate % contents in the sediment samples were determined. Enrichment factor (EF), pollution load and potential ecological risk (PER) indices were calculated to shed light on the ecological effects of heavy metals. The metal content was ranked in descending order of Al > Fe > Mn > Zn > Ni > Cr > Cu > Pb > As > Cd > Hg. The EF values ranged 0.87–1.0 for Cu, 1.04–1.14 for Pb, 1–1.08 for Zn, 0.88–0.95 for Ni, 0.99–1.24 for Mn, 0.89–0.93 for Fe, 0.82–1.01 for As, 0.96–1.19 for Cd, 0.94–1.0 for Cr, and 1.42–1.90 for Hg. Minimal contamination was found for Hg. Pollution load, PER, and toxic risk indices indicated no ecological risk currently. However, considering the PER index for metals individually, a moderate potential risk was detected for Hg. The data obtained from multivariate statistical analyses indicate that Hg and Mn originate from the atmosphere, while other elements have lithogenic sources.     

Cell surface analysis techniques: What do cell preparation protocols do to cell surface properties?

Cell surface analysis often requires manipulation of cells prior to examination. The most commonly employed procedures are centrifugation at different speeds, changes of media during washing or final resuspension, desiccation (either air drying for contact angle measurements or freeze-drying for sensitive spectroscopic analysis, such as X-ray photoelectron spectroscopy), and contact with hydrocarbon (hydrophobicity assays). The effects of these procedures on electrophoretic mobility, adhesion to solid substrata, affinity to a number of Sepharose columns, structural integrity, and cell viability were systematically investigated for a range of model organisms, including carbon- and nitrogen-limited Psychrobacter sp. strain SW8 (glycocalyx-bearing cells), Escherichia coli (gram-negative cells without a glycocalyx), and Staphylococcus epidermidis (gram-positive cells without a glycocalyx). All of the cell manipulation procedures severely modified the physicochemical properties of cells, but with each procedure some organisms were more susceptible than others. Considerable disruption of cell surfaces occurred when organisms were placed in contact with a hydrocarbon (hexadecane). The majority of cells became nonculturable after air drying and freeze-drying. Centrifugation at a high speed (15,000 x g) modified many cell surface parameters significantly, although cell viability was considerably affected only in E. coli. The type of washing or resuspension medium had a strong influence on the values of cell surface parameters, particularly when high-salt solutions were compared with low-salt buffers. The values for parameters obtained with different methods that allegedly measure similar cell surface properties did not correlate for most cells. These results demonstrate that the methods used to prepare cells for cell surface analysis need to be critically investigated for each microorganism so that the final results obtained reflect the nature of the in situ microbial cell surface as closely as possible. There is an urgent need for new, reliable, nondestructive, minimally manipulative cell surface analysis techniques that can be used in situ.     

Dissemination of heavy-metal contamination in surface sediments of the Uzunçayır Dam Lake,Tunceli, Turkey

The objective of this study was to determine the heavy-metal concentrations (Cu, Pb, Zn, Ni, Mn, Fe, As, Cd, Cr, and Hg), evaluate the pollution levels, and determine the concentration of chlorophyll-a and organic carbon in the surface sediments of the Uzunçay?r Dam Lake, Tunceli, Turkey, between 2015 and 2016. In order to evaluate the effect of the pollution level in the study area, the contamination factor (CF), enrichment factor, potential ecological risk index, and pollution load index were used. The concentrations of the studied heavy metals were ordered as follows: Fe > Mn > Ni > Cr > Zn > Cu > Pb > As > Cd > Hg. The highest CF value was found for the Ni element among the studied heavy metals in the Dam Lake. Moreover, the highest CF mean value was found for the As contamination level. According to the toxicity analyses in the study area, the potential toxic effect of sediments was not at a very serious level.     

Did surface temperatures constrain microbial evolution?

The proposition that glaciation may not have occurred before the Cenozoic--albeit not yet a consensus position--nevertheless raises for reconsideration the surface temperature history of the earth. Glacial episodes, from the Huronian (2.3 billion years ago; BYA) through the late Paleozoic (320 to 250 million years ago; MYA) have been critical constraints on estimation of the upper bounds of temperature (Crowley 1983, Kasting and Toon 1989). Once removed, few if any constraints on the upper temperature limit other than life remain. Walker (1982) recognized that life provides an upper limit to temperature in the Precambrian. We propose a more radical concept: the upper temperature limit for viable growth of a given microbial group corresponds to the actual surface temperature at the time of the group's first appearance. In particular, we propose here that two major evolutionary developments--the emergence of cyanobacteria and aerobic eukaryotes--can be used to determine surface temperature in the Precambrian, and that only subsequent cooling mediated by higher plants and then angiosperms permitted what may possibly be the earth's first glaciation in the late Cenozoic.     

Mycobacterium leprae — The outer lipoidal surface

There is now a considerable body of evidence to suggest that the phthiocerol-containing lipids, including the phenolic glycolipids, comprise the so-called “peribacillary substance”, “spherical droplets”, “foamy structures” and “capsular materials” ofMycobacterium leprae. Thus, the phthiocerol-containing lipid capsule may be directly responsible for the intracellular survival ofMycobacterium leprae.     

3′-sialyllactose targets cell surface protein,SIGLEC-3, and induces megakaryocyte differentiation and apoptosis by lipid raft-dependent endocytosis

Glycoconjugate Journal - 3′-sialyllactose is one of the abundant components in human milk oligosaccharides (HMOs) that protect infants from various viral infections in early stages of immune...     

Construction,expression and characterization of the engineered antibody against tumor surface antigen,p185^c—erbB—2

The c-erbB-2 proto-oncogene encodes a 185kD protein p185,which belongs to epidermal growth factor receptor family.Amplification of this gene has been shown to correlate with poor clinical prognosis for certain cancer patients.The monoclonal antibody A21 which directed against p185 specifically inhibits proliferation of tumor cells overexpressing p185,hence allows it to be a candidate for targeted therapy.In order to overcome several drawbacks of murine MAb,we cloned its VH and VL genes and constructed the single-chain FV(scFv)through a peptide linker.The recombinant scFv A21 was expressed in Escherichia coli and purified by the affinity column.Subsequently it was characterized by ELISA,Western blot,cell immunohistochemistry and FACS.All these assays showed the binding activity to extracellular domain(ECD)of p185.Based on those properties of scFvA21,we further constructed the scFv-Fc fusion molecule with a homodimer form and the recombinant product was expressed in mammalian cells.In a series of subsequent analysis this fusion protein showed identical antigen binding site and activity with the parent antibody.These anti-p185 engineered antibodies have promised to be further modified as a tumor targeting drugs,with a view of application in the diagnosis and treatment of human breast cancer.     

Occurrence of Diatom – Diazotrophic association in the coastal surface waters of south Andaman,India

The heterocystous cyanobacterium Richelia intracellularis Schmidt 1901 is well known for its capability to fix atmospheric nitrogen (N₂) in oligotrophic waters. Symbiotic associations of Richelia intracellularis with the diatoms Rhizosolenia hebetata, Rhizosolenia clevei, Rhizosolenia cylindrus and Hemiaulus membranaceus is reported for the first time from the coastal waters of South Andaman, India. In these the symbiotic associations, variations were observed in the number of vegetative cells, trichomes, and the shape of the heterocysts. The highest number of trichomes was observed in Rhizosolenia clevei (14) per host. The trichomes consisted of 9–10 vegetative cells and a spherical heterocyst that was orientiated toward one end of the host diatom cell. In Rhizosolenia hebetata, three trichomes of Richelia intracellularis were present, one trichome at one end with 7–8 vegetative cells and two trichomes at the other end. In Rhizosolenia cylindrus, two trichomes of Richelia were observed, with a spherical heterocyst and 5–6 vegetative cells. An association between Hemiaulus membranaceus and Richelia intracellularis was also observed but with less frequency. Trichomes were observed in the centre of the diatom. By using the cell-specific rates, the amount of new N provided by the Diatom-Diazotrophic Associations was estimated. This is the first record of a symbiotic association of Richelia in diatoms from Andaman coastal waters.     

Spatial and temporal variability of saphrophytic bacteria in the surface waters of Paranaguá and Antonina Bays,Paraná, Brazil

Spatial and temporal variability in the concentration of saprophytic bacteria was investigated in surface waters of Paranaguá and Antonina bays.Seven points along a profile from the entrance of Paranaguá Bay to the innermost part of Antonina Bay, were sampled monthly from November 1985 to November 1986. Temperature, dissolved oxygen, pH and precipitation data were also measured.ZoBell 2216E culture medium was utilized with freshwater and 32% salinity water.Principal component analysis of biotic and abiotic data showed a gradient from the innermost bay to the baymouth bar with an increase in bacteria concentration at Antonina Bay. Significant variation was not observed among sampling stations at Paranaguá Bay, except for February 1986 when there was a homogeneous increase of bacteria throughout both bays in association with an increase in temperature and precipitation. There was also no strong variation of saprophyte numbers at sampling locations near Paranaguá city, despite domestic and harbour waste input.We conclude that the outer region of the estuary is highly influenced by the adjacent ocean and that the inner part has typical estuarine characteristics. The region may be considered little polluted.     

Is the surface layer from hazelnut pollen,which is precipitated by Cuprolinic blue,an effective antigen in hay-fever patients?

Summary In electron micrographs it could be shown that hazelnut (Corylus avellana) pollen grains are covered on their surface by a diffusible 10 nm thick lamellar layer. On pollen surface as well as in pollen extract this layer could be precipitated and stained by the polycationic dye Cuprolinic blue. By subsequent application of both immunogold labeling with serum from a hay-fever patient allergic to tree pollen grains and histochemical detection with Cuprolinic blue this pollen surface layer proved to be an effective antigen.     

Stimulating surface molecules,Th1-polarizing cytokines,proven trafficking—a new protocol for the generation of clinical-grade dendritic cells

Background aimsDendritic cells (DC) have been vigorously investigated as an immunological basis for therapeutic vaccination against cancer and infections, even among patients after allogeneic stem cell transplantation.MethodsEffective induction of cell-mediated immunity strongly depends on the ability of DC to (i) migrate to the draining lymphoid organs mediated by chemokine receptors, (ii) prime T cells through high expression of costimulatory molecules and major histocompatibility complexes and (iii) secret Th1-polarizing cytokines such as Interleukin-12 (IL-12). However, there is no protocol to generate fully matured and functional DC according to methodical requirements of current good manufacturing practice (CGMP) guidelines.ResultsWe established a protocol conforming to CGMP standards that permits the generation of fully matured and functional DC on the basis of cell culture in adherence bags with the use of serum-free media with a maturation cocktail, containing tumor necrosis factor-alpha/Interferon-alpha/polyinosinic:polycytidylic acid. Our DC superiorly display three critical features for an effective induction of cell-mediated immunity without evidence of exhaustion, along with its ability to prime infectious or tumor-specific T cells in a short-term cell culture.ConclusionsOur newly developed protocol offers an attractive method to produce fully matured Th1-polarizing DC with proven migratory and stimulatory capacity for any clinical application according to CGMP standards.     

Transport effects on surface–volume biological reactions

Many cellular reactions involve a reactant in solution binding to or dissociating from a reactant confined to a surface. This is true as well for a BIAcore, an optical biosensor that is widely used to study the interaction of biomolecules. In the flow cell of this instrument, one of the reactants is immobilized on a flat sensor surface while the other reactant flows past the surface. Both diffusion and convection play important roles in bringing the reactants into contact. Usually BIAcore binding data are analyzed using well known expressions that are valid only in the reaction-limited case when the Damk?hler number Da is small. Asymptotic and singular perturbation techniques are used to analyze dissociation of the bound state when Da is small and O(1). Linear and nonlinear integral equations result from the analysis; explicit and asymptotic solutions are constructed for physically realizable cases. In addition, effective rate constants are derived that illustrate the effects of transport on the measured rate constants. All these expressions provide a direct way to estimate the rate constants from BIAcore binding data.     

Can tissue surface tension drive somite formation?

The prevailing model of somitogenesis supposes that the presomitic mesoderm is segmented into somites by a clock and wavefront mechanism. During segmentation, mesenchymal cells undergo compaction, followed by a detachment of the presumptive somite from the rest of the presomitic mesoderm and the subsequent morphological changes leading to rounded somites. We investigate the possibility that minimization of tissue surface tension drives the somite sculpting processes. Given the time in which somite formation occurs and the high bulk viscosities of tissues, we find that only small changes in shape and form of tissue typically occur through cell movement driven by tissue surface tension. This is particularly true for somitogenesis in the zebrafish. Hence it is unlikely that such processes are the sole and major driving force behind somite formation. We propose a simple chemotactic mechanism that together with heightened adhesion can account for the morphological changes in the time allotted for somite formation.     

Adsorption of glycinin and β-conglycinin on silica and cellulose: surface interactions as a function of denaturation, pH, and electrolytes

Soybean proteins have found uses in different nonfood applications due to their interesting properties. We report on the kinetics and extent of adsorption on silica and cellulose surfaces of glycinin and β-conglycinin, the main proteins present in soy. Quartz crystal microgravimetry (QCM) experiments indicate that soy protein adsorption is strongly affected by changes in the physicochemical environment. The affinity of glycinin and the mass adsorbed on silica and cellulose increases (by ca. 13 and 89%, respectively) with solution ionic strength (as it increases from 0 to 100 mM NaCl) due to screening of electrostatic interactions. In contrast, β-conglycinin adsorbs on the same substrates to a lower extent and the addition of electrolyte reduces adsorption (by 25 and 57%, respectively). The addition of 10 mM 2-mercaptoethanol, a denaturing agent, reduces the adsorption of both proteins with a significant effect for glycinin. This observation is explained by the cleavage of disulfide bonds which allows unfolding of the molecules and promotes dissociation into subunits that favors more compact adsorbed layer structures. In addition, adsorption of glycinin onto cellulose decreases with lowering the pH from neutral to pH 3 due to dissociation of the macromolecules, resulting in flatter adsorbed layers. The respective adsorption isotherms fit a Langmuir model and QCM shifts in energy dissipation and frequency reveal multiple-step kinetic processes indicative of changes in adlayer structure.     

Morphological surface characteristics of Streptomyces glaucescens and S. acrimycini,two streptomycetes with “hairy” spores

Summary The ultrastructure of the surface membranes of the spores and aerial hyphae of S. glaucescens and S. acrimycini was studied by means of electron microscopy of air-dried whole mounts, thin sections, negative stainings and freezeetchings. The delicate sheath which envelopes the spore walls produces long protruding appendages which have previously been designated as hairs, a name which is based on silhouette views of untreated whole mounts, where the processes appear long and curled. Freeze-etching and negative staining revealed that the processes are composed of interlacing straight tubular units of varying length. These tubules exhibited a distinct fine structure. It is suggested that they are made of rolled up sheets with a regular striation pattern. The surface membrane of the non-sporulating aerial hyphae has no processes, but a pattern of irregularly arranged and ill-defined rodlets.