Single-Phase and Two-Phase Anaerobic Co-Digestion of Residues from the Treatment Process of Waste Vegetable Oil and Pig Manure

The co-digestion of residues from the pre-treatment process of waste vegetable oil (OW) and pig manure (PM) was performed under different OW/PM feed ratios (1:0, 1:1 and 1:3 v/v) and at organic loading rates ranging from 0.25 to 3.1 kg VS m^?3 day^?1 in lab-scale single-phase (SP) and two-phase (TP) systems. From the experiments, it was observed that digestion of OW alone was inhibitory for the anaerobic degradation. Mixing OW with PM neutralized the negative effects of lipids accumulation and high VS removal efficiencies were realized in both systems (63 and 71 % in SP system and 69 and 72 % in TP system, at 1:1 and 1:3 OW/PM mixtures, respectively). Under the same operational conditions, the methane yield was 0.30 and 0.22 m³ CH₄ kg^?1 VS removed for the SP anaerobic digester and 0.30 and 0.27 m³ CH₄ kg^?1 VS removed for the TP configuration. Additionally, TP digestion presented more stable operation and higher treatment capacity.     

Epithelial cell types of the primary ureter of Helix aspersa: Ultrastructural and cytochemical characteristics

The present study describes the morphological characteristics which determine the structural polarity of the principal and ciliated cells in the primary ureter epithelium of Helix aspersa. These characteristics are analysed on the basis of the function performed by both cell types. The presence of paniculate glycogen and the location of glycoconjugates associated with cell membranes of the epithelial cells is revealed by the method of Thiéry.     

Rapid up-regulation of alpha4 integrin-mediated leukocyte adhesion by transforming growth factor-beta1

The alpha4 integrins (alpha4beta1 and alpha4beta7) are cell surface heterodimers expressed mostly on leukocytes that mediate cell-cell and cell-extracellular matrix adhesion. A characteristic feature of alpha4 integrins is that their adhesive activity can be subjected to rapid modulation during the process of cell migration. Herein, we show that transforming growth factor-beta1 (TGF-beta1) rapidly (0.5-5 min) and transiently up-regulated alpha4 integrin-dependent adhesion of different human leukocyte cell lines and human peripheral blood lymphocytes (PBLs) to their ligands vascular cell adhesion molecule-1 (VCAM-1) and connecting segment-1/fibronectin. In addition, TGF-beta1 enhanced the alpha4 integrin-mediated adhesion of PBLs to tumor necrosis factor-alpha-treated human umbilical vein endothelial cells, indicating the stimulation of alpha4beta1/VCAM-1 interaction. Although TGF-beta1 rapidly activated the small GTPase RhoA and the p38 mitogen-activated protein kinase, enhanced adhesion did not require activation of both signaling molecules. Instead, polymerization of actin cytoskeleton triggered by TGF-beta1 was necessary for alpha4 integrin-dependent up-regulated adhesion, and elevation of intracellular cAMP opposed this up-regulation. Moreover, TGF-beta1 further increased cell adhesion mediated by alpha4 integrins in response to the chemokine stromal cell-derived factor-1alpha. These data suggest that TGF-beta1 can potentially contribute to cell migration by dynamically regulating cell adhesion mediated by alpha4 integrins.     

Effect of superoxide dismutase,allopurinol and glucocorticoids on liver and lung metallothionein induction by endotoxin in the rat

Liver and lung metallothionein (MT) levels were increased by endotoxin. The administration of superoxide dismutase (SOD) or allopurinol (ALLO) before (30–60 min) or after (24–32 h) the endotoxin treatment either increased or did not affect the effect of endotoxin on MT levels, depending on the particular treatment and tissue. SOD and ALLO also increased liver and lung MT levels in control rats. In contrast, liver MT levels tended to be decreased by the glucocorticoid prednisolone (PRED) when administered before the endotoxin and were significantly decreased when it was administered after endotoxin. The effect of PRED on lung MT levels was completely different, since it decreased the effect of endotoxin when injected before the lipopolysaccharide, but increased it when injected after the endotoxin. Liver lipid peroxidation, as measured by thiobarbituric acid reactants (TBARs), increased after endotoxin in the liver but not in the lung, an effect even potentiated in some cases by the antioxidants studied. As expected, tissue MT and TBARs could not be correlated.     

Naproxen Adsorption-Desorption in a Sandy Aquifer Matrix: Characterisation of Hysteretic Behavior at Two Different Temperature Values

Adsorption/desorption processes (sorption isotherms) of Naproxen in a sandy aquifer matrix sediment were investigated using batch tests to compare Naproxen sorption behavior at 15°C and 25°C. Both temperatures are representative of the aquifer media and environmental conditions. Adsorption was well described by linear isotherms with low sorption affinity to aquifer material (K_d of 0.4 μg kg^?1) at both temperatures (15°C and 25°C). Desorption isotherm coefficients at 15°C and 25°C were 5.0 and 4.9, respectively. Naproxen hysteresis indices were between 9.98 and 10.8, indicating that a Naproxen fraction may be irreversibly fixed in the aquifer media, being higher at 25°C (10.88) compared to 15°C, showing a decreasing trend with increasing compound concentration at 15°C. The low sorption of Naproxen leads to potential leaching to groundwater if present in irrigation water, and its prevalence in an aquifer media when directly injected in wells for groundwater recharge.     

Neuron-Type Specific Functions of DNT1, DNT2 and Spz at the Drosophila Neuromuscular Junction

Retrograde growth factors regulating synaptic plasticity at the neuromuscular junction (NMJ) in Drosophila have long been predicted but their discovery has been scarce. In vertebrates, such retrograde factors produced by the muscle include GDNF and the neurotrophins (NT: NGF, BDNF, NT3 and NT4). NT superfamily members have been identified throughout the invertebrates, but so far no functional in vivo analysis has been carried out at the NMJ in invertebrates. The NT family of proteins in Drosophila is formed of DNT1, DNT2 and Spätzle (Spz), with sequence, structural and functional conservation relative to mammalian NTs. Here, we investigate the functions of Drosophila NTs (DNTs) at the larval NMJ. All three DNTs are expressed in larval body wall muscles, targets for motor-neurons. Over-expression of DNTs in neurons, or the activated form of the Spz receptor, Toll ^10b, in neurons only, rescued the semi-lethality of spz ² and DNT1 ⁴¹ , DNT2 ^e03444 double mutants, indicating retrograde functions in neurons. In spz ² mutants, DNT1 ⁴¹ , DNT2 ^e03444 double mutants, and upon over-expression of the DNTs, NMJ size and bouton number increased. Boutons were morphologically abnormal. Mutations in spz and DNT1,DNT2 resulted in decreased number of active zones per bouton and decreased active zone density per terminal. Alterations in DNT function induced ghost boutons and synaptic debris. Evoked junction potentials were normal in spz ² mutants and DNT1 ⁴¹ , DNT2 ^e03444 double mutants, but frequency and amplitude of spontaneous events were reduced in spz ² mutants suggesting defective neurotransmission. Our data indicate that DNTs are produced in muscle and are required in neurons for synaptogenesis. Most likely alterations in DNT function and synapse formation induce NMJ plasticity leading to homeostatic adjustments that increase terminal size restoring overall synaptic transmission. Data suggest that Spz functions with neuron-type specificity at the muscle 4 NMJ, and DNT1 and DNT2 function together at the muscles 6,7 NMJ.     

A new class of calcium channels activated by glucose in human pancreatic beta-cells

Single calcium-channel currents were recorded from membrane patches of cultured beta-cells dissociated from human islets of Langerhans. In the absence of exogenous glucose, low frequency spontaneous calcium-channel openings of small amplitude (-0.34 +/- 0.02 pA at 0 mV pipet potential) were observed in all membrane patches examined (25 mM Ca2+ in the patch pipet). The frequency of channel openings was rather insensitive to the membrane potential across the patch (range from ca 0 to 60 mV pipet potential; chord conductance 4.9 +/- 0.2 pS). Addition of glucose induced a dose-dependent increase in the frequency of openings of the Ca2(+)-channel (from now on referred to as the CaG-channel). A few minutes after the addition of glucose (greater than or equal to 11 mM), bursts of action potentials were often observed which were elicited only if Ca2+ was present in the solution bathing the beta-cells. Application of glucose in the presence of mannoheptulose (11 mM), a blocker of the hexokinase controlling the first stage of glycolysis, had no effect and the activity of the CaG-channel remained at its resting level. The readily permeant mitochondrial substrate 2-keto-isocaproate (KIC, 10 mM) was as effective as glucose in eliciting action potentials from cells forming part of cell aggregates. The activity of the CaG-channel was significantly increased by KIC (11 mM). Although spike and Ca2(+)-channel activity were markedly stimulated by glucose or KIC in all cells examined, regular bursts of action potentials were seen only if the patch was formed on beta-cells which were part of a cell aggregate. Mannoheptulose (11 mM) prevented the activation of the CaG-channel by glucose (11 mM) but not by KIC (11 mM). Once activated, the CaG-channel remained active even after excision of the patch. We propose that the physiological control of this Ca2(+)-channel is mediated by one or more products of glucose metabolism.