Delayed yet persistent hippocampal molecular and structural alteration after learning: new players in the debate on time-dependent long-lasting memory processes

Two articles in this issue concern the presynaptic structural remodeling and the molecular events that are important novel mechanisms underlying long-term memory storage processes

Research of wastewater tertiary treatment / Tretinio nuotekų valymo tyrimai

Small individual household wastewater treatment plants not always operate well. Consequently, the concentrations of ammonium nitrogen and phosphate phosphorus are exceeded. The aim of the work was to found the most effective material for wastewater tertiary treatment and propose environmentally friendly ways to solve fresh water problem. Three filter fillings (foam-glass, zeolite and biochar) were tested. As a result, we have got a following conclusion, foam-glass removed phosphate phosphorus most effectively (efficacy – 14−91%) and against ammonium nitrogen, comparatively effective was zeolite (efficacy – 29−100%). Santrauka Individualaus buitinių nuotekų valymo įrenginiai ne visada dirba efektyviai. Dėl to fiksuojami nitratų azoto, amonio azoto, bendrojo azoto, bendrojo fosforo ir fosfatų fosforo koncentracijų išvalytose nuotekose viršijimai. Darbo tikslas surasti efektyvias medžiagas tretiniam nuotekų valymui ir pasiūlyti šiai problemai spręsti aplinkai draugiškas technologijas, kad išvalytos nuotekos nepakenktų aplinkos kokybei. Buvo tirti trys filtro užpildai (pustiklis, ceolitas, bioanglis). Gauti rezultatai ir išvados, kad pustiklis efektyviau (efektyvumas – 14−91%) šalina iš nuotekų fosfatų fosforą, o ceolitas – amonio azotą (efektyvumas – 29−100 %). Reikšminiai žodžiai: tretinis nuotekų valymas, bendrojo fosforo ir bendrojo azoto valymas, ceolitas, pustiklis, bioanglis

The genus Daphne : a review of its traditional uses, phytochemistry and pharmacology

The genus Daphne belongs to the Thymeleaceae family and contains over 90 species that are distributed in Asia, Europe and parts of North Africa. The species of the genus Daphne are used in the traditional medicine of China, Tibet, Korea, and the Middle East for the treatment of various conditions. A broad range of studies has shown the significant biological potential of these species as sources of biologically and pharmacologically active compounds. Daphne species are a source of several classes of valuable phytochemicals such as coumarins, flavonoids, lignans, steroids and different classes of terpenes. The phytochemical diversity of this genus is demonstrated by over 350 secondary metabolites isolated from various species. The genus possesses a broad spectrum of biological activities including antibacterial, antifungal, antioxidant, analgesic, anti-inflammatory, cytotoxic, antiviral, abortive and haemostatic effects. A variety of bioactive secondary metabolites found in this genus may have potential use in pharmaceutical, cosmetic and food industries. Thus, species belonging to the genus Daphne can be considered an important source both for the treatment of various disorders, due to the presence of a plethora of bioactive constituents with potent bioactivities, and as possible leads in the discovery and synthesis of new medications

Quantitative analysis of long-form aromatase mRNA in the male and female rat brain.

In vitro studies show that estrogens acutely modulate synaptic function in both sexes. These acute effects may be mediated in vivo by estrogens synthesized within the brain, which could fluctuate more rapidly than circulating estrogens. For this to be the case, brain regions that respond acutely to estrogens should be capable of synthesizing them. To investigate this question, we used quantitative real-time PCR to measure expression of mRNA for the estrogen-synthesizing enzyme, aromatase, in different brain regions of male and female rats. Importantly, because brain aromatase exists in two forms, a long form with aromatase activity and a short form with unknown function, we targeted a sequence found exclusively in long-form aromatase. With this approach, we found highest expression of aromatase mRNA in the amygdala followed closely by the bed nucleus of the stria terminalis (BNST) and preoptic area (POA); we found moderate levels of aromatase mRNA in the dorsal hippocampus and cingulate cortex; and aromatase mRNA was detectable in brainstem and cerebellum, but levels were very low. In the amygdala, gonadal/hormonal status regulated aromatase expression in both sexes; in the BNST and POA, castration of males down-regulated aromatase, whereas there was no effect of estradiol in ovariectomized females. In the dorsal hippocampus and cingulate cortex, there were no differences in aromatase levels between males and females or effects of gonadal/hormonal status. These findings demonstrate that long-form aromatase is expressed in brain regions that respond acutely to estrogens, such as the dorsal hippocampus, and that gonadal/hormonal regulation of aromatase differs among different brain regions

Data from: Quantitative analysis of long-form aromatase mRNA in the male and female rat brain

In vitro studies show that estrogens acutely modulate synaptic function in both sexes. These acute effects may be mediated in vivo by estrogens synthesized within the brain, which could fluctuate more rapidly than circulating estrogens. For this to be the case, brain regions that respond acutely to estrogens should be capable of synthesizing them. To investigate this question, we used quantitative real-time PCR to measure expression of mRNA for the estrogen-synthesizing enzyme, aromatase, in different brain regions of male and female rats. Importantly, because brain aromatase exists in two forms, a long form with aromatase activity and a short form with unknown function, we targeted a sequence found exclusively in long-form aromatase. With this approach, we found highest expression of aromatase mRNA in the amygdala followed closely by the bed nucleus of the stria terminalis (BNST) and preoptic area (POA); we found moderate levels of aromatase mRNA in the dorsal hippocampus and cingulate cortex; and aromatase mRNA was detectable in brainstem and cerebellum, but levels were very low. In the amygdala, gonadal/hormonal status regulated aromatase expression in both sexes; in the BNST and POA, castration of males down-regulated aromatase, whereas there was no effect of estradiol in ovariectomized females. In the dorsal hippocampus and cingulate cortex, there were no differences in aromatase levels between males and females or effects of gonadal/hormonal status. These findings demonstrate that long-form aromatase is expressed in brain regions that respond acutely to estrogens, such as the dorsal hippocampus, and that gonadal/hormonal regulation of aromatase differs among different brain regions

Activity-dependent Wnt 7 dendritic targeting in hippocampal neurons: plasticity- and tagging-related retrograde signaling mechanism?

Wnt proteins have emerged as transmembrane signaling molecules that regulate learning and memory as well as synaptic plasticity at central synapses (Inestrosa and Arenas (2010) Nat Rev Neurosci 11:77-86; Maguschak and Ressler (2011) J Neurosci 31:13057-13067; Tabatadze et al. (2012) Hippocampus 22: 1228-1241; Fortress et al. (2013) J Neurosci 33:12619-12626). For example, there is both a training-selective and Wnt isoform-specific increase in Wnt 7 levels in hippocampus seven days after spatial learning in rats (Tabatadze et al. (2012) Hippocampus 22: 1228-1241). Despite growing interest in Wnt signaling pathways in the adult brain, intracellular distribution and release of Wnt molecules from synaptic compartments as well as their influence on synaptic strength and connectivity remain less well understood. As a first step in such an analysis, we show here that Wnt 7 levels in primary hippocampal cells are elevated by potassium or glutamate activation in a time-dependent manner. Subsequent Wnt 7 elevation in dendrites suggests selective somato-dendritic trafficking followed by transport from dendrites to their spines. Wnt 7 elevation is also TTX-reversible, establishing that its elevation is indeed an activity-dependent process. A second stimulation given 6 h after the first significantly reduces Wnt 7 levels in dendrites 3 h later as compared to non-stimulated controls suggesting activity-dependent Wnt 7 release from dendrites and spines. In a related experiment designed to mimic the release of Wnt 7, exogenous recombinant Wnt 7 increased the number of active zones in presynaptic terminals as indexed by bassoon. This suggests the formation of new presynaptic release sites and/or presynaptic terminals. Wnt signaling inhibitor sFRP-1 completely blocked this Wnt 7-induced elevation of bassoon cluster number and cluster area. We suggest that Wnt 7 is a plasticity-related protein involved in the regulation of presynaptic plasticity via a retrograde signaling mechanism as previously proposed (Routtenberg (1999) Trends in Neuroscience 22:255-256). These findings provide support for this proposal, which offers a new perspective on the synaptic tagging mechanism

Wnt transmembrane signaling and long-term spatial memory

Transmembrane signaling mechanisms are critical for regulating the plasticity of neuronal connections underlying the establishment of long-lasting memory (e.g., Linden and Routtenberg (1989) Brain Res Rev 14:279–296; Sossin (1996) Trends Neurosci 19:215–218; Mayr and Montminy (2001) Nat Rev Mol Cell Biol 2:599–609; Chen et al. (2011) Nature 469:491–497). One signaling mechanism that has received surprisingly little attention in this regard is the well-known Wnt transmembrane signaling pathway even though this pathway in the adult plays a significant role, for example, in postsynaptic dendritic spine morphogenesis and presynaptic terminal neurotransmitter release (Inestrosa and Arenas (2010) Nat Rev Neurosci 11:77–86). The present report now provides the first evidence of Wnt signaling in spatial information storage processes. Importantly, this Wnt participation is specific and selective. Thus, spatial, but not cued, learning in a water maze selectively elevates the levels in hippocampus of Wnt 7 and Wnt 5a, but not the Wnt 3 isoform, indicating behavioral selectivity and isoform specificity. Wnt 7 elevation is subfield-specific: granule cells show an increase with no detectable change in CA3 neurons. Wnt 7 elevation is temporally specific: increased Wnt signaling is not observed during training, but is seen 7 days and, unexpectedly, 30 days later. If the Wnt elevation after learning is activity-dependent, then it may be possible to model this effect in primary hippocampal neurons in culture. Here, we evaluate the consequence of potassium or glutamate depolarization on Wnt signaling. This represents, to our knowledge, the first demonstration of an activation-dependent elevation of Wnt levels and surprisingly an increased number of Wnt-stained puncta in neurites suggestive of trafficking from the cell body to neuronal processes, probably dendrites. It is proposed that Wnt signaling pathways regulate long-term information storage in a behavioral-, cellular-, and isoform-specific manner

mRNA sequence of rat aromatase.

<p>Exon boundaries in the rat mRNA sequence of cytochrome P450 (NCBI Reference Sequence: NM_017085.2) are marked in bold and highlighted in grey. An arrow indicates beginning of the translated region in the long form of aromatase. Untranslated regions have been grayed out. The 90 bp fragment (715–805) that was amplified in our qPCR and RT-PCR analyses is highlighted in yellow. The region that is thought to be missing in the truncated form of the enzyme involves the exons 2 and 3 and hence encompasses the sequence that was targeted in our study. The boxed nucleotides in the sequence indicate the start and the end of the RNA probe that protected only the long form of aromatase in ribonuclease protection assays <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100628#pone.0100628-Roselli3" target="_blank">[10]</a>.</p

Effect of gonadal/hormonal status on aromatase mRNA expression in different brain regions.

<p>Expression levels of the long form of aromatase were studied in the amygdala, BNST, POA, dorsal hippocampus, and cingulate cortex of castrated male, gonadally intact male, ovx female and ovx+E2 female rats. Each panel represents a different brain region. For each panel, qPCR amplification curves with relative fluorescent units (RFU) and the area punch dissected (red circle in the schematics of brain coronal sections, adapted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100628#pone.0100628-Paxinos1" target="_blank">[48]</a>) are shown at the top. C_T (cycle threshold) values on the amplification curve indicate the number of cycles required for the fluorescent signal to cross the threshold, which was set at 10 standard deviations above mean fluorescence generated during baseline cycles. Relative aromatase mRNA expression for each brain region is shown in bar graphs (ovx females set as 1.0) with representative images of agarose gels showing RT-PCR products for amplified aromatase (Aro) and GAPDH DNA fragments at the bottom. In the amygdala <b>(A)</b>, aromatase mRNA levels were affected by both sex (p = 0.006) and gonadal/hormonal status (p = 0.01), whereas in the BNST <b>(B)</b> and the POA <b>(C)</b>, gonadally intact males showed the highest aromatase mRNA expression, which was significantly different from all other groups; ** significant difference between intact males and other groups (p<0.01). In contrast, in the dorsal hippocampus <b>(D)</b> and cingulate cortex <b>(E)</b> aromatase mRNA levels did not differ among the groups.</p