Antilipoxygenase activity of compounds from Hypericum perforatum

The main biologically active constituents of Hypericum species are flavonoids (quercetin, isoquercitrin, hyperoside, rutin), biflavonoids and naphthodianthrones (hypericin, pseudohypericin). Lipoxygenase is the key enzyme in the biosynthesis of leukotriens, which have been postulated to play an important role in the pathophysiology of several inflammatory and allergic diseases. This work deals with the investigation of potential antilipoxygenase activity of different compounds and extracts isolated from Hypericum perforatum L. The highest inhibitory effect was exhibited by flavonoid derivative hyperoside (IC₅₀ 5.768 × 10⁻⁶ M). Acetone and ethanolic extracts caused also an inhibition of lipoxygenase. On the basis of inhibitory effect of compounds tested we assume that the most of them may be involved in the antiinflammatory principles of Hypericum perforatum L.     

Theiler's Murine Encephalomyelitis Virus L* Amino Acid Position 93 Is Important for Virus Persistence and Virus-Induced Demyelination

The DA strain and other members of the TO subgroup of Theiler''s murine encephalomyelitis virus (TMEV) induce a persistent central nervous system infection associated with an inflammatory white matter demyelinating disease. TO subgroup strains synthesize an 18-kDa protein, L*, out of frame with the polyprotein from an initiation codon 13 nucleotides downstream from the polyprotein''s AUG codon. We previously generated a mutant virus from our infectious DA full-length clone that has a change of the L* AUG codon to ACG (with no change in the polyprotein''s amino acid sequence). Studies of this mutant virus showed that L* was key to the TO subgroup phenotype because the mutant had a decreased ability to persist and demyelinate. This work was initially called into question because a similar mutant derived from a different full-length DA infectious clone persisted and demyelinated similarly to wild-type DA virus (O. van Eyll and T. Michiels, J. Virol. 74:9071-9077, 2000). We now report that (i) the sequence of the L* coding region differs in the two infectious clones, resulting in a Ser or Leu as the predicted amino acid at position 93 of L* (with no change in the polyprotein''s amino acid sequence), (ii) the difference in this amino acid is key to the phenotypic differences between the two mutants, and (iii) the change in amino acid 93 may affect L* phosphorylation. It is of interest that this amino acid only appears critical in determining the virus phenotype when L* is present in a significantly reduced amount (i.e., following translation from an ACG initiating codon).The DA strain and other members of the TO subgroup of Theiler''s murine encephalomyelitis virus (TMEV) induce an acute subclinical gray matter central nervous system (CNS) infection in SJL mice that is followed by a chronic inflammatory white matter demyelinating disease; virus persists in the CNS for the life of the mouse (for a review, see reference 16). The DA virus demyelinating disease serves as a model of multiple sclerosis since the two are similar in white matter pathology and both disease processes appear to be immune mediated. In contrast, the GDVII strain and other members of the GDVII subgroup of TMEV cause an acute fatal neuronal infection and fail to persist.The study of the TMEV model system is an especially attractive one for molecular pathogenesis studies because TMEV is a relatively simple virus with only four structural proteins in the virion; the nucleotide sequence and deduced amino acid sequence are known for several TMEV strains; the three-dimensional crystal structure of two TMEV strains has been solved; infectious TMEV clones are available, easing the preparation of recombinant or mutated viruses; TMEV-neutralizing monoclonal antibody sites and T-cell epitopes are known; and the experimental and natural host for TMEV, the mouse, is easily manipulated and is well studied immunologically and genetically. An understanding of the determinants of the TMEV disease phenotypes (neurovirulence, virus persistence, restricted infection, demyelination) may be valuable in clarifying the pathogenesis of picornaviral diseases, as well as and non-virus-induced CNS diseases such as amyotrophic lateral sclerosis and multiple sclerosis.The genome of all picornaviruses contains a long open reading frame that is translated into a polyprotein. One remarkable feature of the TO subgroup strains is that an 18-kDa protein, L*, is synthesized out of frame with the polyprotein from an initiation codon that is 13 nucleotides (nt) downstream from the polyprotein''s AUG codon (8) (Fig. ​(Fig.1A1A).Open in a separate windowFIG. 1.The DA virus genome (A) and parental wild-type and L* mutant viruses (B). (A) The DA virus genome with a 5′ untranslated region (5′ UTR), polyprotein (LP1P2P3), and 3′ UTR, as well as L*, which is out of frame with the polyprotein''s reading frame; the regions of the genome are not drawn to size. The polyprotein''s initiating AUG codon is at nt 1066, while the L* AUG codon is at nt 1079. (B) Parts of the nucleotide sequences of the L* proteins of two wild-type parental DA viruses (DA, TMDA) and the mutant L* proteins derived from one or the two parental wild-type infectious clones, with a replacement of the initiating AUG codon with an ACG codon, as well as a C or U at nt 1359 coding for a Ser or Leu at amino acid 93.We previously engineered a mutant virus, called DAL*-1, which had a change of the L* AUG codon to ACG (but with no change in the amino acid sequence of the polyprotein) (4) from our infectious clone pDAFL3 (17) (Fig. ​(Fig.1B).1B). The DAL*-1 virus had a decreased ability to persist and demyelinate, suggesting that L* is key to the distinctive TO subgroup phenotype. Subsequent studies showed that L* interfered with virus clearance by CD4⁺ T cells, allowing the virus to persist (10). This work was initially called into question by Michiels and colleagues (21) because a mutant DA virus, OV48, with the same mutation as DAL*-1 (as well as an additional replacement of an AUG codon, in the fifth codon of the L* reading frame, to ACG) had no effect on the ability of the DA virus to persist or demyelinate; however, this mutant was engineered from a different full-length DA clone, pTMDA1 (11). In a subsequent study, they further investigated the importance of L* in virus persistence and demyelination by demonstrating that an L* mutant that contained a stop codon in the L* sequence (with no change in the polyprotein''s amino acid sequence) had a significant decrease in virus persistence and demyelination (22). We suspected that the contrasting disease phenotypes induced by the DAL*-1 and OV48 viruses might have resulted from a sequence difference(s) in L*. In the present study, we demonstrate that a change in L* of nucleotide (nt) 1356/amino acid 93 led to the change in phenotype of DAL*-1 versus OV48.     

Involvement of lipoxygenase in elicitor-stimulated sanguinarine accumulation in Papaver somniferum suspension cultures

The involvement of lipoxygenase (LOX, EC 1.13.11.12) in elicitor-induced opium poppy defense response was investigated. Papaver somniferum L. suspension cultures were treated with abiotic elicitor methyl jasmonate (MJ), fungal elicitor (Botrytis cinerea homogenate) and phenidone (specific inhibitor of LOX) to determine the involvement of this enzyme in production of sanguinarine, the major secondary metabolite of opium poppy cultures. P. somniferum suspension cultures responded to elicitor treatment with strong and transient increase of LOX activity followed by sanguinarine accumulation. LOX activity increased in elicited cultures, reaching 9.8 times of the initial value at 10 h after MJ application and 2.9 times after B. cinerea application. Sanguinarine accumulated to maximal levels of 169.5 ± 12.5 μg g^?1 dry cell weight in MJ-elicited cultures and 288.0 ± 10.0 μg g^?1 dry cell weight in B. cinerea-elicited cultures. The treatment of cells with phenidone before elicitor addition, significantly reduced sanguinarine production. The relative molecular weight of P. somniferum LOX (83 kDa) was estimated by using immunobloting and its pH optimum was shown to be pH 6.5.     

Mixed lineage kinase 3 mediates gp120IIIB-induced neurotoxicity

Overexpression of gp120, the major coat protein of the HIV-1 virus, in central glial cells, or treatment of neurons with gp120 in culture, produces apoptotic neuronal death. Here we demonstrate that CEP-1347 (KT7515), an inhibitor of mixed lineage kinase 3 (MLK3), an upstream activator of JNK, inhibits gp120IIIB-induced apoptosis of hippocampal neurons. Furthermore, expression of wild type MLK3 in hippocampal pyramidal neurons enhanced gp120IIIB-induced neurotoxicity, whereas expression of a dominant negative MLK3 protected neurons from the toxic effects of the glycoprotein. These results indicate a role for MLK3 signaling in gp120IIIB-induced neuronal death, and suggest potential clinical utility of CEP-1347 in inhibiting the progression of AIDS dementia.     

Spatial Structure and Distribution of Small Pelagic Fish in the Northwestern Mediterranean Sea

Understanding the ecological and anthropogenic drivers of population dynamics requires detailed studies on habitat selection and spatial distribution. Although small pelagic fish aggregate in large shoals and usually exhibit important spatial structure, their dynamics in time and space remain unpredictable and challenging. In the Gulf of Lions (north-western Mediterranean), sardine and anchovy biomasses have declined over the past 5 years causing an important fishery crisis while sprat abundance rose. Applying geostatistical tools on scientific acoustic surveys conducted in the Gulf of Lions, we investigated anchovy, sardine and sprat spatial distributions and structures over 10 years. Our results show that sardines and sprats were more coastal than anchovies. The spatial structure of the three species was fairly stable over time according to variogram outputs, while year-to-year variations in kriged maps highlighted substantial changes in their location. Support for the McCall''s basin hypothesis (covariation of both population density and presence area with biomass) was found only in sprats, the most variable of the three species. An innovative method to investigate species collocation at different scales revealed that globally the three species strongly overlap. Although species often co-occurred in terms of presence/absence, their biomass density differed at local scale, suggesting potential interspecific avoidance or different sensitivity to local environmental characteristics. Persistent favourable areas were finally detected, but their environmental characteristics remain to be determined.     

1α,25-dihydroxyvitamin D(3) mechanism of action: modulation of L-type calcium channels leading to calcium uptake and intermediate filament phosphorylation in cerebral cortex of young rats

The involvement of calcium-mediated signaling pathways in the mechanism of action of 1α,25-dihydroxyvitamin D(3) (1,25D) is currently demonstrated. In this study we found that 1,25D induces nongenomic effects mediated by membrane vitamin D receptor (VDRm) by modulating intermediate filament (IF) phosphorylation and calcium uptake through L-type voltage-dependent calcium channels (L-VDCC) in cerebral cortex of 10 day-old rats. Results showed that the mechanism of action of 1,25D involves intra- and extracellular calcium levels, as well as the modulation of chloride and potassium channels. The effects of L-VDCCs on membrane voltage occur over a broad potential range and could involve depolarizing or hyperpolarizing coupling modes, supporting a cross-talk among Ca(2+) uptake and potassium and chloride channels. Also, the Na(+)/K(+)-ATPase inactivation by ouabain mimicked the 1,25D action on (45)Ca(2+) uptake. The Na(+)/K(+)-ATPase inhibition observed herein might lead to intracellular Na(+) accumulation with subsequent L-VDCC opening and consequently increased (45)Ca(2+) (calcium, isotope of mass 45) uptake. Moreover, the 1,25D effect is dependent on the activation of the following protein kinases: cAMP-dependent protein kinase (PKA), Ca(2+)/calmodulin-dependent protein kinase (PKCaMII), phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase p38 (p38(MAPK)). The modulation of calcium entry into neural cells by the 1,25D we are highlighting, might take a role in the regulation of a plethora of intracellular processes. Considering that vitamin D deficiency can lead to brain illness, 1,25D may be a possible candidate to be used, at least as an adjuvant, in the pharmacological therapy of neuropathological conditions.     

Statistical ecology comes of age

The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1–4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data.     

Influence of EDTA complexing agent on biopreparation of linen fabric

In this work the ‘EDTA–enzyme–substrate’ interaction was investigated in linen biopreparation. The effect of EDTA on the degradation of non-cellulosic constituents during bioscouring with pectinase enzyme was investigated in detail. Greige linen fabric was treated with pectinase, pectinase supplemented with ethylenediamine-tetra-acetic acid (EDTA), and EDTA pre-treatment followed by pectinase, in a tumble agitated bath. Adding EDTA to the enzyme solution accelerated the degree of hydrolysis and resulted in higher reducing sugar liberation and more efficient calcium ion extraction, indicating a synergistic effect of enzyme and EDTA. However, when EDTA was applied as a pre-treatment, a decrease in the efficiency of the subsequent enzymatic hydrolysis was observed.