Investigations of boron uptake at the cellular level

The efficiency of recovery of P by iron oxide-impregnated filter paper, as used in the new P_i test for soil phosphorus, was found to depend on the method used for impregnating the paper with iron oxide and could range from as little as 28% to more than 98%. The greatest efficiency of recovery was obtained with filter papers which had been washed with deionised water following iron oxide-impregnation. These filter papers were also found to give the most reproducible results. ei]{gnB E}{fnClothier}     

The argonaut shell: gas-mediated buoyancy control in a pelagic octopus

Argonauts (Cephalopoda: Argonautidae) are a group of rarely encountered open-ocean pelagic octopuses with benthic ancestry. Female argonauts inhabit a brittle ‘paper nautilus’ shell, the role of which has puzzled naturalists for millennia. The primary role attributed to the shell has been as a receptacle for egg deposition and brooding. Our observations of wild argonauts have revealed that the thin calcareous shell also functions as a hydrostatic structure, employed by the female argonaut to precisely control buoyancy at varying depths. Female argonauts use the shell to ‘gulp’ a measured volume of air at the sea surface, seal off the captured gas using flanged arms and forcefully dive to a depth where the compressed gas buoyancy counteracts body weight. This process allows the female argonaut to attain neutral buoyancy at depth and potentially adjust buoyancy to counter the increased (and significant) weight of eggs during reproductive periods. Evolution of this air-capture strategy enables this negatively buoyant octopus to survive free of the sea floor. This major shift in life mode from benthic to pelagic shows strong evolutionary parallels with the origins of all cephalopods, which attained gas-mediated buoyancy via the closed-chambered shells of the true nautiluses and their relatives.     

Effects of thyrotropin and N6,O2′-dibutyryl cyclic 3′,5′-adenosine monophosphate on prostaglandin levels in thyroid

We have shown that TSH increases PG levels in isolated bovine thyroid cells. We now report that TSH also increases PG levels in rat and mouse thyroid, and that these effects may be mediated via cyclic AMP. PG and cyclic AMP levels in intact rat and mouse thyroid lobes were measured by radioimmunoassay. During 60-min incubations at 37°C, 25 mU/ml TSH effected a 75–83% increase in PGE₁ and PGF_2α ”equivalents“ in rat thyroid; parallel measurements of endogenous cyclic AMP in these intact thyroid lobes revealed that maximal TSH-induced increase in cyclic AMP also required 60-min incubations. In mouse thyroid, 5 mU/ml TSH increased PGE₁ and PGF_2α levels 38–82% above basal; this TSH effect was evident within 15 min of incubation, thus mimicking the time-course of TSH-induced increase in mouse thyroid cyclic AMP. Exogenous DBcAMP, 0.5 to 3 mM, effected a dose-related increase in mouse thyroid PG levels. The stimulatory effects of both TSH and DBcAMP on mouse thyroid PG levels were abolished by aspirin and indomethacin. These studies suggest that TSH-induced increase in endogenous PG levels in thyroid may be mediated by cyclic AMP.     

The principal glucocorticoid binding macromolecule in hepatoma cells in culture is similar to corticosteroid Binder II of rat liver cytosol

Reuber H-35 hepatoma (H4-II-E-C3) and HTC cells are known to retain differentiated corticosteroid induced functions in cell culture and to bind corticosteroids to macromolecules in cytosol which subsequently enter the cell nuclear fraction. Using both cell types we have demonstrated the major macromolecular fraction in cytosol to have properties (elution position from DEAE columns, pI, ³H-dexamethasone binding), very similar to those of rat liver corticosteroid Binder II which may be the hormone receptor.     

Paper mill sludge-based carbon quantum dots as a specifically ratiometric fluorescent probe for the sensitive and selective detection of coptisine

Coptisine (COP), one of the bioactive components in Rhizoma Coptidis, has many pharmacological effects. Meanwhile, the determination of COP is essential in pharmacological and clinical applications. Herein, we prepared carbon quantum dots (CQDs) by one-step oil-thermal method using paper mill sludge (PMS) as precursor, and developed a ratiometric fluorescence method for the determination of COP. The structural and optical properties of PMS-CQDs were evaluated through high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), ultraviolet-visible (UV-vis), fluorescence, zeta potential and fluorescence lifetime experiments. Fluorescence intensity ratio at 550 nm and 425 nm (I₅₅₀/I₄₂₅) was recorded as an index for quantitative detection of COP. The detection concentration of COP ranges from 0.1 to 50 μM in good linear correlation (R² = 0.9974) with a limit of detection of 0.028 μM (3σ/k). The quenching mechanism was deduced to be inner filter effect and static quenching. The ratiometric fluorescent probe showed impressive selectivity and sensitivity towards COP, and was successfully applied to the detection of COP in human urine with expected recoveries (95.22–111.00%) and relative standard deviations (0.46–2.95%), indicating that our developed method has a great application prospect in actual sample detection.     

Effects of elevated atmospheric CO2 and/or O3 on intra- and interspecific competitive ability of aspen

Three model communities of trembling aspen (monoculture, and mixed with either paper birch or sugar maple) were grown for seven years in elevated atmospheric CO(2) and O(3) using Free Air CO(2) Enrichment (FACE) technology. We utilized trends in species' importance, calculated as an index of volume growth and survival, as indications of shifting community composition. For the pure aspen communities, different clones emerged as having the highest change in relative importance values depending on the pollutant exposure. In the control and elevated CO(2) treatments, clone 42E was rapidly becoming the most successful clone while under elevated O(3), clone 8 L emerged as the dominant clone. In fact, growth of clone 8 L was greater in the elevated O(3) treatment compared to controls. For the mixed aspen-birch community, importance of aspen and birch changed by - 16 % and + 62 %, respectively, in the controls. In the treatments, however, importance of aspen and birch changed by - 27 % and + 87 %, respectively, in elevated O(3), and by - 10 % and + 45 %, respectively, in elevated CO(2). Thus, the presence of elevated O(3) hastened conversion of stands to paper birch, whereas the presence of elevated CO(2) delayed it. Relative importance of aspen and maple changed by - 2 % and + 3 %, respectively, after seven years in the control treatments. But in elevated O(3), relative importance of aspen and maple changed by - 2 % and + 5 %, respectively, and in elevated CO(2) by + 9 and - 20 %, respectively. Thus, elevated O(3) slightly increases the rate of conversion of aspen stands to sugar maple, but maple is placed at a competitive disadvantage to aspen under elevated CO(2).     

Energy use and recovery strategies within wastewater treatment and sludge handling at pulp and paper mills

This paper presents an inclusive approach with focus on energy use and recovery in wastewater management, including wastewater treatment (WWT) and sludge handling. Process data from three Swedish mills and a mathematical model were used to evaluate seven sludge handling strategies. The results indicate that excess energy use in WWT processes counters the potential energy recovery in the sludge handling systems. Energy use in WWT processes is recommended to aim for sufficient effluent treatment, not for sludge reduction. Increased secondary sludge production is favourable from an energy point of view provided it is used as a substrate for heat, biogas or electricity production.     

EVOLUTION OF IDENTITY SIGNALS: FREQUENCY‐DEPENDENT BENEFITS OF DISTINCTIVE PHENOTYPES USED FOR INDIVIDUAL RECOGNITION

Identifying broad‐scale evolutionary processes that maintain phenotypic polymorphisms has been a major goal of modern evolutionary biology. There are numerous mechanisms, such as negative frequency‐dependent selection, that may maintain polymorphisms, although it is unknown which mechanisms are prominent in nature. Traits used for individual recognition are strikingly variable and have evolved independently in numerous lineages, providing an excellent model to investigate which factors maintain ecologically relevant phenotypic polymorphisms. Theoretical models suggest that individuals may benefit by advertising their identities with distinctive, recognizable phenotypes. Here, we test the benefits of advertising one's identity with a distinctive phenotype. We manipulated the appearance of Polistes fuscatus paper wasp groups so that three individuals had the same appearance and one individual had a unique, easily recognizable appearance. We found that individuals with distinctive appearances received less aggression than individuals with nondistinctive appearances. Therefore, individuals benefit by advertising their identity with a unique phenotype. Our results provide a potential mechanism through which negative frequency‐dependent selection may maintain the polymorphic identity signals in P. fuscatus. Given that recognition is important for many social interactions, selection for distinctive identity signals may be an underappreciated and widespread mechanism underlying the evolution of phenotypic polymorphisms in social taxa.     

Performance of improved bacterial cellulose application in the production of functional paper

Aim: The purpose of this work was to study the feasibility of producing economic flame retardant bacterial cellulose (BC) and evaluating its behaviour in paper production. Methods and Results: This type of BC was prepared by Gluconacetobacter subsp. xylinus and substituting the glucose in the cultivation medium by glucose phosphate as a carbon source; as well as using corn steep liquor as a nitrogen source. The investigated processing technique did not dispose any toxic chemicals that pollute the surroundings or cause unacceptable effluents, making the process environmentally safe. The fire retardant behaviour of the investigated BC has been studied by non‐isothermal thermogravimetric analysis (TGA & DTGA). The activation energy of each degradation stage and the order of degradation were estimated using the Coats–Redfern equation and the least square method. Strength, optical properties, and thermogravimetric analysis of BC‐phosphate added paper sheets were also tested. Conclusions: The study confirmed that the use of glucose phosphate along with glucose was significant in the high yield production of phosphate containing bacterial cellulose (PCBC1); more so than the use of glucose phosphate alone (PCBC2). Incorporating 5% of the PCBC with wood pulp during paper sheet formation was found to significantly improve kaolin retention, strength, and fire resistance properties as compared to paper sheets produced from incorporating bacterial cellulose (BC). Significance and Impact of the Study: This modified BC is a valuable product for the preparation of specialized paper, in addition to its function as a fillers aid.     

Oxidative catalysts for the transformation of phenolic pollutants: a brief review

Phenolics are often produced as wastes by several industrial and agricultural activities. Many of these compounds and their derivatives are extremely dangerous to living organisms, because they are highly toxic and thus represent a serious environmental concern.

Conventional remediation methods of phenol-polluted systems have some disadvantages due to high cost, time-consuming procedures and formation of toxic residues. Conversely, the use of oxidative catalysts, both enzymatic or inorganic, is a promising alternative technology to address the clean up of such wastes. Oxidative enzymes and inorganic compounds, both naturally occurring in soil, behave as biotic and abiotic catalysts and support the transformation of phenolic compounds. The complete mineralization of phenolic pollutants as well as the formation of polymeric products, often less toxic than their precursors, may occur.

The present paper gives a brief review of many aspects concerning the properties of biotic and abiotic catalytic agents effective in the transformation of phenolic compounds. The main mechanisms of the processes as well as their feasibility for catalytic practical applications will be addressed. Examples of their potentiality in the detoxification of phenol-polluted systems will be provided, as well.