The potential for using the needle litter of Scotch pine (Pinus sylvestris L.) as a raw material for particleboard manufacturing

Particleboard panels were made from various wood particle/needle litter of Scotch pine (Pinus sylvestris L.) mixtures bonded with urea formaldehyde resin. Litter was characterized by having higher solubility's in alcohol-benzene, with diluting alkali and hot water, and resulted in lower pH values than those of wood particles. The mechanical properties (modulus of rupture, modulus of elasticity, and internal bond strength) of boards containing up to 6.25% litter were lower than those of panels made from wood particles. However, needle litter usage improved the physical property (thickness swelling) and decay resistance of the panels, significantly. Panels consist of 6.25% and 12.50% needle litter met the minimum EN standard requirements of mechanical properties for general-purposes. Particleboards contain more than 50% needle litter had the required level of thickness swelling for 24 h immersion.     

Elimination of HIV-1-Infected Primary T Cell Reservoirs in an In Vitro Model of Latency

Establishment of long-lived cellular reservoirs of HIV-1 represents a major therapeutic challenge to virus eradication. In this study, we utilized a human primary cell model of HIV-1 latency to evaluate the requirements for efficient virus reactivation from, and the selective elimination of, latently infected human T cells. Ectopic expression of BCL2 supported the replication and spread of R5-tropic HIV-1 in activated CD4⁺ T cells. After IL-2 withdrawal, the HIV-1-infected T cells survived as resting cells for several months. Unexpectedly, these resting T cells continue to produce detectable levels of infectious virus, albeit at a lower frequency than cells maintained in IL-2. In the presence of HIV-1 inhibitors, reactivation of the resting T cells with γc-cytokines and allogeneic dendritic cells completely extinguished HIV-1 infectivity. We also evaluated the ability of the bacterial LukED cytotoxin to target and kill CCR5-expressing cells. After γc-cytokine stimulation, LukED treatment eliminated both HIV-1-infected resting cells and the non-infected CCR5⁺ cells. Importantly, complete clearance of in vitro HIV-1 reservoirs by LukED required a lower threshold of cytokine signals relative to HIV-1 inhibitors. Thus, the primary T cell-based HIV-1 latency model could facilitate the development of novel agents and therapeutic strategies that could effectively eradicate HIV-1.     

Expression and Function of TNF and IL-1 Receptors on Human Regulatory T Cells

Regulatory T cells (Tregs) suppress immune activation and are critical in preventing autoimmune diseases. While the ability of Tregs to inhibit proliferation of other T cells is well established, it is not yet clear whether Tregs also modulate inflammatory cytokines during an immune response. Here, we show that the expression of inflammatory cytokine receptors IL-1R1 and TNFR2 were higher on resting mature Tregs compared to naïve or memory T cells. While upon activation through the T cell receptor (TCR), expression of IL-1R1 and TNFR2 were upregulated on all T cell subsets, IL-1R1 maintained significantly higher expression on activated Tregs as compared to other T cell subsets. The decoy receptor for IL-1 (IL-1R2) was not expressed by any of the resting T cells but was rapidly upregulated and preferentially expressed upon TCR-stimulation on Tregs. In addition, we found that Tregs also expressed high levels of mRNA for IL-1 antagonist, IL-1RA. TCR-stimulation of naïve T cells in the presence of TGFβ, which induces FOXP3 expression, however did not result in upregulation of IL-1R1 or IL-1R2. In addition, ectopic expression of FOXP3 in non-Tregs, while causing significant upregulation of IL-1R1 and IL-1R2, did not achieve the levels seen in bona fide Tregs. We also determined that resting human Tregs expressing IL-1R1 did not have higher suppressive capacity compared to IL-1R1- Tregs, suggesting that IL-1R1 does not discriminate suppressive resting Tregs in healthy individuals. Functionally, activated human Tregs displayed a capacity to neutralize IL-1β, which suggests a physiological significance for the expression of IL-1 decoy receptor on Tregs. In conclusion, our findings that human Tregs preferentially express receptors for TNF and IL-1 suggest a potential function in sensing and dampening local inflammation.     

The Tyrosine Kinase Btk Regulates the Macrophage Response to Listeria monocytogenes Infection

In this study we investigated the role of Bruton''s tyrosine kinase (Btk) in the immune response to the Gram-positive intracellular bacterium Listeria monocytogenes (Lm). In response to Lm infection, Btk was activated in bone marrow-derived macrophages (BMMs) and Btk ^−/− BMMs showed enhanced TNF-α, IL-6 and IL-12p40 secretion, while type I interferons were produced at levels similar to wild-type (wt) BMMs. Although Btk-deficient BMMs displayed reduced phagocytosis of E. coli fragments, there was no difference between wt and Btk ^−/− BMMs in the uptake of Lm upon infection. Moreover, there was no difference in the response to heat-killed Lm between wt and Btk ^−/− BMMs, suggesting a role for Btk in signaling pathways that are induced by intracellular Lm. Finally, Btk ^−/− mice displayed enhanced resistance and an increased mean survival time upon Lm infection in comparison to wt mice. This correlated with elevated IFN-γ and IL-12p70 serum levels in Btk ^−/− mice at day 1 after infection. Taken together, our data suggest an important regulatory role for Btk in macrophages during Lm infection.     

Adequate magnesium nutrition mitigates adverse effects of heat stress on maize and wheat

Aims

Heat stress is a growing concern in crop production because of global warming. In many cropping systems heat stress often occurs simultaneously with other environmental stress factors such as mineral nutrient deficiencies. This study aimed to investigate the role of adequate magnesium (Mg) nutrition in mitigating the detrimental effects of heat stress on wheat (Triticum aestivum) and maize (Zea mays).

Methods

Wheat and maize plants were grown in solution culture with low or adequate Mg supply at 25/22 °C (light/dark). Half of the plants were, then, exposed to heat stress at 35/28 °C (light/dark). Development of leaf chlorosis and changes in root and shoot growth, chlorophyll and Mg concentrations as well as the activities of major antioxidative enzymes were quantified in the experimental plants. Additionally, maize plants were analyzed for the specific weights (e.g., dry or fresh weight per a given leaf surface area) and soluble carbohydrate concentrations of sink and source leaves.

Results

Visual leaf symptoms of Mg deficiency were aggravated in wheat and maize when exposed to heat stress. In both species, root growth was more sensitive to Mg deficiency than shoot growth, and the shoot-to-root ratios peaked when heat stress was combined with Mg deficiency. Magnesium deficiency markedly reduced soluble carbohydrate concentrations in young leaf; but resulted in substantial increase in source leaves. Magnesium deficiency also increased activities of antioxidative enzymes, especially when combined with heat stress. The highest activities of superoxide dismutase (up to 80 % above the control), glutathione reductase (up to 250 % above the control) and ascorbate peroxidase (up to 300 % above the control) were measured when Mg-deficient plants were subjected to heat, indicating stimulated formation of reactive oxygen species (ROS) in Mg deficient leaves under heat stress.

Conclusions

Magnesium deficiency increases susceptibility of wheat and maize plants to heat stress, probably by increasing oxidative cellular damage caused by ROS. Ensuring a sufficiently high Mg supply for crop plants through Mg fertilization is a critical factor for minimizing heat-related losses in crop production.     

Effects of excess vitamin B6 intake on cerebral cortex neurons in rat: an ultrastructural study

The aim of this study was to investigate whether excess of vitamin B6 leads to ultrastructural changes in cerebral cortex of forty-eight healthy albino rats which were included in the study. Saline solution was injected to to the control groups (CG-10, n = 12 for 10 days; CG-15, n = 12 for 15 days; CG-20, n=12 for 20 days). The three experimental groups (EG-10, n = 12; EG-15, n = 12; EG-20, n = 12) were treated with 5 mg/kg vitamin B6 daily for 10 days (EG-10), 15 days (EG-15) and 20 days (EG-20). Brain tissues were prepared by glutaraldehyde-osmium tetroxide double fixation for ultrastructural analysis. No significant changes were observed in the control groups. The ultrastructural analysis revealed that the numbers of damaged mitochondria, lipofuscin granules and vacuoles were significantly higher in all the experimental groups than in the control groups (p < 0.05). However, synaptic density was significantly decreased in the experimental groups as compared to the control groups (p < 0.05). The results suggest that the excess of vitamin B6 intake causes damage to the cerebral cortex due to cellular intoxication and decreased synaptic density. Thus, careful attention should be paid to the time and dose of vitamin B6 recommended for patients who are supplemented with this vitamin.     

Impacts of calcium addition and different oil types and levels on in vitro rumen fermentation and digestibility

This in vitro study was designed to investigate the effects of calcium addition to substrates differing in source and level of oil on fermentation, gas production, and digestibility parameters. Substrates were made from basal mixtures containing three levels of calcium salt (0, 1, and 2% CaCl2) to contain three levels (3, 6, and 9%) of two types (sunflower and soy) of oil. After collecting from two Holstein bulls and mixing with buffer, rumen fluid was used to incubate the resulting 18 mixtures in duplicate. Ionizable calcium, pH and NH3-N concentration were measured during incubation. Gas production was measured at 6, 12, 24, and 48 h after incubation. Kinetics parameters of gas production and in vitro dry matter digestibility (IVDMD) were calculated from regression coefficients of an exponential equation and a linear equation, respectively. Data were analysed using 3-way ANOVA with repeated measure option in which the parameter time was a subplot. Oil type did not affect pH and ionizable calcium concentration. There were linear increases and decreases in pH and ionizable calcium concentration in response to increasing oil and calcium levels, respectively. However, with increasing oil levels there were no interactions between calcium addition and oil level on pH and ionizable calcium concentration. None of the treatments affected NH3-N concentration. The amount of gas produced from substrates containing sunflower oil was greater than soy oil (41.7 vs. 40.5 ml). Cumulative gas production and amount of gas production from insoluble but slowly fermentable portion of the supplemental mixtures linearly decreased and linearly increased as oil and calcium levels increased in the substrates, respectively. However, interactions of calcium addition and oil level on gas production and kinetics of gas production were lacking. Oil type did not affect IVDMD. Despite lacking main effects, interaction of calcium addition and oil level indicated that increasing calcium level alleviated depression in IVDMD resulting from increasing oil level. In conclusion, increasing oil level depressed, whereas calcium addition stimulated ruminal fermentation. Improvement in IVDMD may partially support that calcium addition alleviates the adverse effects of oil and that more calcium is needed when diets are supplemented with increasing amounts of oil.     

Investigation of sugar binding kinetics of the E. coli sugar/H+ symporter XylE using solid-supported membrane-based electrophysiology

Bacterial transporters are difficult to study using conventional electrophysiology because of their low transport rates and the small size of bacterial cells. Here, we applied solid-supported membrane–based electrophysiology to derive kinetic parameters of sugar translocation by the Escherichia coli xylose permease (XylE), including functionally relevant mutants. Many aspects of the fucose permease (FucP) and lactose permease (LacY) have also been investigated, which allow for more comprehensive conclusions regarding the mechanism of sugar translocation by transporters of the major facilitator superfamily. In all three of these symporters, we observed sugar binding and transport in real time to determine K_M, V_max, K_D, and k_obs values for different sugar substrates. K_D and k_obs values were attainable because of a conserved sugar-induced electrogenic conformational transition within these transporters. We also analyzed interactions between the residues in the available X-ray sugar/H⁺ symporter structures obtained with different bound sugars. We found that different sugars induce different conformational states, possibly correlating with different charge displacements in the electrophysiological assay upon sugar binding. Finally, we found that mutations in XylE altered the kinetics of glucose binding and transport, as Q175 and L297 are necessary for uncoupling H⁺ and d-glucose translocation. Based on the rates for the electrogenic conformational transition upon sugar binding (>300 s⁻¹) and for sugar translocation (2 s⁻¹ − 30 s⁻¹ for different substrates), we propose a multiple-step mechanism and postulate an energy profile for sugar translocation. We also suggest a mechanism by which d-glucose can act as an inhibitor for XylE.