Rapid Response Mechanism Research Articles

Metallothionein-II improves motor function recovery and increases spared tissue after spinal cord injury in rats

After spinal cord injury (SCI), a complex cascade of pathophysiological processes rapidly damages the nervous tissue. The initial damage spreads to the surrounding tissue by different mechanisms, including oxidative stress. We have recently reported that the induction of metallothionein (MT) protein is an endogenous rapid-response mechanism after SCI. Since the participation of MT in neuroprotective processes after SCI is still unknown, the aim of the present study was to evaluate the possible neuroprotective effect of exogenously administered MT-II during the acute phase after SCI in rats. Female Wistar rats weighing 200–250g were submitted to spinal cord contusion by means of a computer-controlled device (NYU impactor). Rats received several doses of MT-II (3.2, 10 and 100μg) at 2 and 8h after SCI. Results of the BBB scale were statistically analysed using an ANOVA of repeated-measures, followed by Tukey's test. Among the three doses tested, only 10 and 100μg were able to significantly increase (p<0.05) BBB scale scores eight weeks after SCI from a mean of 7.88 in the control group, to means of 12.63 and 10.88 for the 10 and 100μg doses of MT-II, respectively. The amount of spared tissue was also higher in the groups treated with 10 and 100μg, as compared to the control group values. Results from the present study demonstrate a significant neuroprotective effect of exogenously administered MT-II. Further studies are needed in order to characterize the mechanisms involved in this neuroprotective action.

Complexity by Design

This article discusses various engineering revolutions taking place to deal with challenges of complex systems’ design. Engineers who design complex systems have to understand how the various components of a system fit together and anticipate how the interactions between these components could lead to failure. The development of sophisticated expert system software that can provide rapid and intuitive access to vast amounts of data on materials and design features of available components also enables an individual engineer to tap into the expertise of many others. Adaptive risk management structures, such as those used in high-reliability organizations, which rely on expertise, planning, and communication, can help to reduce the uncertainty of human factor risk. Some automated control and feedback systems use embedded sensors and extremely rapid response mechanisms to prevent or limit damage from a failure far faster than a human operator could. The experts suggest that the rise of complex systems creates a challenge to traditional ways of engineering.

Callosciurus squirrels: worldwide introductions, ecological impacts and recommendations to prevent the establishment of new invasive populations

Abstract Rodents are traded as pet species, a practice that frequently results in new introduced populations. This is particularly true for tree squirrels where, often, only a few founders can establish viable colonies. Here, we review the worldwide introductions, ecology and impacts of two tree squirrel species, Callosciurus erythraeus and Callosciurus finlaysonii, and discuss the elements of a strategy to reduce squirrel introductions and settlements. C. erythraeus has established viable populations in Argentina, France, The Netherlands, Hong Kong and Japan. An introduction to Belgium may have been stopped successfully. C. finlaysonii has been introduced to Italy, Singapore and Japan. After 1950, the mean number of introduction events was one every two years. The most evident damage caused by these species is bark stripping that can be severe and may significantly impact trees and timber plantations. Data on negative impacts to native species are reported but have not yet been formally quantified. Both squirrel species carried with them parasites from the native range into the new habitats, leading to the introduction of other species. The ability of tree squirrels to establish themselves successfully, often from only a few founders, combined with their human appeal make them high‐risk species, and the pet trade should be considered as a high‐risk pathway for new introductions. A proactive approach to preventing new introductions should therefore include trade restrictions, and should be combined with public education initiatives at national and European scales. Tree squirrels represent an ‘alien species conundrum’. Experience from the UK and Italy has shown that if action is delayed until introductions are recognized as a problem, it is generally too late to control populations effectively, due to logistic, legal or economic reasons, or due to lack of public support. In the case of new populations, a rapid response mechanism is therefore critical. Once established, populations may become invasive and difficult or impossible to control.

Proteome analysis of Physcomitrella patens exposed to progressive dehydration and rehydration

Physcomitrella patens is an extremely dehydration-tolerant moss. However, the molecular basis of its responses to loss of cellular water remains unclear. A comprehensive proteomic analysis of dehydration- and rehydration-responsive proteins has been conducted using quantitative two-dimensional difference in-gel electrophoresis (2D-DIGE), and traditional 2-D gel electrophoresis (2-DE) combined with MALDI TOF/TOF MS. Of the 216 differentially-expressed protein spots, 112 and 104 were dehydration- and rehydration-responsive proteins, respectively. The functional categories of the most differentially-expressed proteins were seed maturation, defence, protein synthesis and quality control, and energy production. Strikingly, most of the late embryogenesis abundant (LEA) proteins were expressed at a basal level under control conditions and their synthesis was strongly enhanced by dehydration, a pattern that was confirmed by RT-PCR. Actinoporins, phosphatidylethanolamine-binding protein, arabinogalactan protein, and phospholipase are the likely dominant players in the defence system. In addition, 24 proteins of unknown function were identified as novel dehydration- or rehydration-responsive proteins. Our data indicate that Physcomitrella adopts a rapid protein response mechanism to cope with dehydration in its leafy-shoot and basal expression levels of desiccation-tolerant proteins are rapidly upgraded at high levels under stress. This mechanism appears similar to that seen in angiosperm seeds.

Translational control mechanisms in metabolic regulation: critical role of RNA binding proteins, microRNAs, and cytoplasmic RNA granules

Regulated cell metabolism involves acute and chronic regulation of gene expression by various nutritional and endocrine stimuli. To respond effectively to endogenous and exogenous signals, cells require rapid response mechanisms to modulate transcript expression and protein synthesis and cannot, in most cases, rely on control of transcriptional initiation that requires hours to take effect. Thus, co- and posttranslational mechanisms have been increasingly recognized as key modulators of metabolic function. This review highlights the critical role of mRNA translational control in modulation of global protein synthesis as well as specific protein factors that regulate metabolic function. First, the complex lifecycle of eukaryotic mRNAs will be reviewed, including our current understanding of translational control mechanisms, regulation by RNA binding proteins and microRNAs, and the role of RNA granules, including processing bodies and stress granules. Second, the current evidence linking regulation of mRNA translation with normal physiological and metabolic pathways and the associated disease states are reviewed. A growing body of evidence supports a key role of translational control in metabolic regulation and implicates translational mechanisms in the pathogenesis of metabolic disorders such as type 2 diabetes. The review also highlights translational control of apolipoprotein B (apoB) mRNA by insulin as a clear example of endocrine modulation of mRNA translation to bring about changes in specific metabolic pathways. Recent findings made on the role of 5'-untranslated regions (5'-UTR), 3'-UTR, RNA binding proteins, and RNA granules in mediating insulin regulation of apoB mRNA translation, apoB protein synthesis, and hepatic lipoprotein production are discussed.

Experimental assembly of foraminiferal communities from coastal propagule banks

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 437:1-11 (2011) - DOI: https://doi.org/10.3354/meps09296 FEATURE ARTICLE Experimental assembly of foraminiferal communities from coastal propagule banks Susan T. Goldstein1,*, Elisabeth Alve2 1Department of Geology, University of Georgia, Athens, Georgia 30602, USA 2Department of Geosciences, University of Oslo, PO Box 1047 Blindern, 0316 Oslo, Norway *Email: sgoldst@uga.edu ABSTRACT: Benthic foraminifera (protists) have long been recognized as sensitive indicators in studies on natural and human-induced environmental, paleo-environmental, and climate change. These wide-ranging applications are founded on more than a century of field-based investigations in which environmental data were related to species distributions, and have subsequently been refined by the development of chemical proxies and a variety of culture-based studies. The recent discovery of foraminiferal propagule banks that occur in the fine-sediment fraction of marine depositional settings provides a novel experimental tool for examining the ecology of benthic foraminifera, their processes of dispersal, and the responses of multi-species assemblages to changing environmental conditions. In the ‘propagule method’ presented here, we use experimental arrays in which foraminifera are grown from propagule banks under different controlled abiotic conditions. We examined the roles of temperature, salinity, and site (exposed vs. protected) in structuring coastal assemblages and show that, because individual species respond differently, distinct assemblages grew from the same propagule bank under different environmental regimes. Temperature was the most important factor distinguishing experimental assemblages, whereas exposure of the collection site (e.g. to waves and currents, that promote or limit species dispersal to and from each site) was most important in determining species richness. The diversity of the propagule bank therefore imparts resilience to foraminiferal associations and provides a rapid-response mechanism for changing environments. This method further provides a tool for documenting changes in coastal assemblages that potentially result from warming or cooling climates. KEY WORDS: Dispersal · Foraminifera · Propagules · Community assembly · Sapelo Island Full text in pdf format Information about this Feature Article Supplementary material NextCite this article as: Goldstein ST, Alve E (2011) Experimental assembly of foraminiferal communities from coastal propagule banks. Mar Ecol Prog Ser 437:1-11. https://doi.org/10.3354/meps09296 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 437. Online publication date: September 15, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

Cryo‐hydrologic warming: A potential mechanism for rapid thermal response of ice sheets

Cryo‐Hydrologic (CH) warming is proposed as a potential mechanism for rapid thermal response of glaciers and ice sheets to climate warming. We present a simple parameterization to incorporate CH warming in thermal models of ice sheets using a dual‐continuum concept, which treats ice and the cryo‐hydrologic system (CHS) as overlapping continua with heat exchange between them. The presence of liquid water in the CHS due to surface melt leads to warming of the ice. The magnitude and time‐scale of CH warming is controlled by the average spacing between elements of the CHS, which is often of the order of just 10's of meters. The corresponding time‐scale of thermal response is of the order of years‐decades, in contrast to conventional estimates of thermal response time‐scales based on vertical conduction through ice (∼102–3 m thick), which are of the order of centuries to millennia. We show that CH warming is already occurring along the west coast of Greenland. Increased temperatures resulting from CH warming will reduce ice viscosity and thus contribute to faster ice flow.

Mitogen-activated protein kinase (MAPK) pathways mediate embryonic responses to culture medium osmolarity by regulating Aquaporin 3 and 9 expression and localization, as well as embryonic apoptosis

In order to advance the development of culture conditions and increase the potential for supporting normal preimplantation embryo development in vitro, it is critical to define the mechanisms that early embryos utilize to survive in culture. We investigated the mechanisms that embryos employ in response to culture medium osmolarity. We hypothesized that mitogen-activated protein kinase (MAPK) pathways mediate responses to hyperosmotic stress by regulating Aquaporin (AQP) 3 and 9 expression as well as embryonic apoptosis. Real-time reverse transcription and polymerase chain reaction and whole-mount immunofluorescence were used to determine the relative mRNA levels and protein localization patterns of AQP 3 and 9 after hyperosmotic medium treatment. At 6 and 24 h, a significant increase in Aqp 3 and 9 mRNA was observed in the sucrose hyperosmotic treatment compared with standard medium and glycerol controls. Blockade of MAPK14/11 negated the increase in Aqp 3 and 9 mRNA levels, whereas culture in a MAPK8 blocker did not. Hyperosmotic sucrose treatment significantly increased embryonic apoptosis which was negated in the presence of MAPK8 blocker, but not MAPK14/11 blocker. MAPK14/11 activation is a component of the rapid adaptive stress response mechanism that includes the effects of AQP mRNA expression and protein localization, whereas the MAPK8 pathway is a regulator of apoptosis.

Rapid response mechanism of pi cell

The rapid response mechanism of pi cell is investigated in detail using one elastic constant and small angle approximation. The improving times of the decay time for pi cell driven by undershoot and normal method compared with that for a Freedericksz cell are calculated and it decreases with the increasing driven voltage for the undershoot method but is larger than that for the normal method. The author’s results show that the same gray-to-gray response times can be obtained using undershoot method but cannot using normal method.

Rapid and slow modulation of nitrate reductase activity in the red macroalga Gracilaria chilensis (Gracilariales, Rhodophyta): influence of different nitrogen sources

Nitrate is one of the most important stimuli in nitrate reductase (NR) induction, while ammonium is usually an inhibitor. We evaluated the influence of nitrate, ammonium or urea as nitrogen sources on NR activity of the agarophyte Gracilaria chilensis. The addition of nitrate rapidly (2 min) induced NR activity, suggesting a fast post-translational regulation. In contrast, nitrate addition to starved algae stimulated rapid nitrate uptake without a concomitant induction of NR activity. These results show that in the absence of nitrate, NR activity is negatively affected, while the nitrate uptake system is active and ready to operate as soon as nitrate is available in the external medium, indicating that nitrate uptake and assimilation are differentially regulated. The addition of ammonium or urea as nitrogen sources stimulated NR activity after 24 h, different from that observed for other algae. However, a decrease in NR activity was observed after the third day under ammonium or urea. During the dark phase, G. chilensis NR activity was low when compared to the light phase. A light pulse of 15 min during the dark phase induced NR activity 1.5-fold suggesting also fast post-translational regulation. Nitrate reductase regulation by phosphorylation and dephosphorylation, and by protein synthesis and degradation, were evaluated using inhibitors. The results obtained for G. chilensis show a post-translational regulation as a rapid response mechanism by phosphorylation and dephosphorylation, and a slower mechanism by regulation of RNA synthesis coupled to de novo NR protein synthesis.

Rethinking Ethnology in the Spanish Context

This paper' discusses Spanish ethnology and its current place in Spanish scholarship. The purpose is to examine possible future directions for the field. After first examining the history of ethnology in Spain, we then turn to examining the role of ethnologists in European societies today, as well as the concept of emergency ethnology. This last refers to the need for developing tools and theories to enable ethnologists to activate rapid-response mechanisms in crisis or emergency situations, and in that sense or context, serve as a meaningful social force.

Molecular and Cellular Requirements for Enhanced Antigen Cross-Presentation to CD8 Cytotoxic T Lymphocytes

MHC class I-mediated cross-priming of CD8 T cells by APCs is critical for CTL-based immunity to viral infections and tumors. We have shown previously that tumor-secreted heat shock protein gp96-chaperoned peptides cross prime CD8 CTL that are specific for genuine tumor Ags and for the surrogate Ag OVA. We now show that tumor-secreted heat shock protein gp96-chaperoned peptides enhance the efficiency of Ag cross-priming of CD8 CTL by several million-fold over the cross-priming activity of unchaperoned protein alone. Gp96 also acts as adjuvant for cross-priming by unchaperoned proteins, but in this capacity gp96 is 1000-fold less active than as a peptide chaperone. Mechanistically, the in situ secretion of gp96-Ig by transfected tumor cells recruits and activates dendritic cells and NK cells to the site of gp96 release and promotes CD8 CTL expansion locally. Gp96-mediated cross-priming of CD8 T cells requires B7.1/2 costimulation but proceeds unimpeded in lymph node-deficient mice, in the absence of NKT and CD4 cells and without CD40L. Gp96-driven MHC I cross-priming of CD8 CTL in the absence of lymph nodes provides a novel mechanism for local, tissue-based CTL generation at the site of gp96 release. This pathway may constitute a critically important, early detection, and rapid response mechanism that is operative in parenchymal tissues for effective defense against tissue damaging antigenic agents.

Invited Review Mechanism

After a detailed assessment of the College's rapid response and service review mechanism, the professional standards and regulation division has upgraded the service and renamed it the 'invited review mechanism' (IRM). Here we examine the process of the review and the new arrangements in place to support surgeons and hospitals in providing high quality surgical services.

Identifying the roles of the ocean and atmosphere in creating a rapid equatorial response to a Southern Ocean anomaly

Recent research has identified a rapid ocean response mechanism to salinity anomalies in the Southern Ocean using an idealised ocean model. Here we examine the relative importance of the ocean and atmosphere in creating an equatorial response to a Southern Ocean anomaly. Using a coupled climate model with realistic bottom topography and land relief, two rapid teleconnections are produced from a high latitude anomaly. An equatorial ocean response can be seen after 30 days. The mechanism producing this response is shown to rely on barotropic and baroclinic oceanic wave propagation. A second, atmospheric, response is seen in the Northern Hemisphere (NH) high latitudes, driven by atmospheric Rossby waves. The ocean quickly responds to the atmospheric signal above it, resulting in sea surface temperature anomalies at NH high latitudes.

Estren Behaves as a Weak Estrogen Rather than a Nongenomic Selective Activator in the Mouse Uterus

A proposed membrane-mediated mechanism of rapid nongenomic response to estrogen has been the intense focus of recent research. Estren, a synthetic steroid, is reported to act selectively through a rapid membrane-mediated pathway, rather than through the classical nuclear estrogen receptor (ER)-mediated pathway, to maintain bone density in ovariectomized mice without uterotropic effects. To evaluate the mechanism and physiological effects of estren, we studied responses in adult ovariectomized mice. In a 3-d uterine bioassay, we found that 300 microg estren significantly increased uterine weight; in comparison, a more maximal response was seen with 1 mug estradiol (E2). The estren response was partly ERalpha independent, because ERalpha knockout (alphaERKO) uteri also exhibited a more moderate weight increase. Estren induced epithelial cell proliferation in wild-type, but not alphaERKO, mice, indicating ERalpha dependence of the epithelial growth response. Examination of estren-regulated uterine genes by microarray indicated that early (2 h) changes in gene expression are similar to the early responses to E2. These gene responses are ERalpha dependent, because they are not seen in alphaERKO mice. Later estren-induced changes in gene expression (24 h) are blunted compared with those seen 24 h after E2. In contrast to early genes, these later estren responses are independent of ERalpha, because the alphaERKO shows a similar response to estren at 24 h. We found that E2 or estren treatments lead to depletion of ERalpha in the uterine cytosol fraction and accumulation in the nuclear fraction within 30-60 min, consistent with the ability of estren to regulate genes through a nuclear ERalpha rather than a nongenomic mechanism. Interestingly, estren, but not E2, induces accumulation of androgen receptor (AR) in the nuclear fraction of both wild-type and alphaERKO samples, suggesting that AR might be involved in the later ERalpha-independent genomic responses to estren. In conclusion, our studies suggest that estren is weakly estrogenic in the mouse uterus and might induce nuclear ERalpha- and AR-mediated responses. Given its activity in our uterine model, the use of estren as a bone-selective clinical compound needs to be reconsidered.

Epidermal Growth Factor-induced Rapid Retinoblastoma Phosphorylation at Ser780 and Ser795 Is Mediated by ERK1/2 in Small Intestine Epithelial Cells

The retinoblastoma protein Rb is critical for the regulation of mammalian cell cycle entry. Hypophosphorylated Rb is considered to be the active form and directs G1 arrest, while hyperphosphorylated Rb permits the transition from G1 to S phase for cell proliferation. Upon stimulation by various growth factors, Rb appears to be phosphorylated by a cascade of phosphorylation events mediated mainly by kinases associated with cyclins D and E. Here we report that in prototype small intestine crypt stem cells (RIEC-6), stimulation with either epidermal growth factor or fetal bovine serum results in an unexpected rapid and sustained Rb phosphorylation at sites Ser780, Ser795, and Thr821 which precedes cyclin D1 expression, cyclin D1/cdk4 complex formation, and cdk4 kinase activity. Rb phosphorylation at Ser780 and Ser795 is prevented by MEK, but not phosphatidylinositol 3-kinase, inhibitors. In vitro, Rb is directly phosphorylated by active ERK1/2 as shown by [gamma-32P]ATP labeling. The phosphorylation sites are further directed to Ser780 and Ser795 by kinase assays using recombined active ERK1/2 or immunoprecipitated phospho-ERK1/2 from mitogen stimulated cells. Pull-down assays revealed that Rb interacts with active ERK1/2 but not their inactive unphosphorylated forms. Upon EGF stimulation, phosphorylated ERK1/2 co-immunoprecipitates together with phosphorylated Rb. Collectively, these results demonstrate a novel rapid Rb phosphorylation at specific sites induced by mitogen stimulation in epithelial cells of the small intestine. These data specifically identify ERK1/2 as the kinase responsible for Rb phosphorylation targeted to sites Ser780 and Ser795. It appears that ERK1/2 could be an important link between a mitogenic signal directly to Rb, thereby providing a rapid response mechanism between mitogen stimulation and cell cycle machinery.

Stimulating effect of adaptogens: an overview with particular reference to their efficacy following single dose administration

Plant adaptogens are compounds that increase the ability of an organism to adapt to environmental factors and to avoid damage from such factors. The beneficial effects of multi-dose administration of adaptogens are mainly associated with the hypothalamic-pituitary-adrenal (HPA) axis, a part of the stress-system that is believed to play a primary role in the reactions of the body to repeated stress and adaptation. In contrast, the single dose application of adaptogens is important in situations that require a rapid response to tension or to a stressful situation. In this case, the effects of the adaptogens are associated with another part of the stress-system, namely, the sympatho-adrenal-system (SAS), that provides a rapid response mechanism mainly to control the acute reaction of the organism to a stressor. This review focuses primarily on the SAS-mediated stimulating effects of single doses of adaptogens derived from Rhodiola rosea, Schizandra chinensis and Eleutherococcus senticosus. The use of these drugs typically generates no side effects, unlike traditional stimulants that possess addiction, tolerance and abuse potential, produce a negative effect on sleep structure, and cause rebound hypersomnolence or 'come down' effects. Furthermore, single administration of these adaptogens effectively increases mental performance and physical working capacity in humans. R. rosea is the most active of the three plant adaptogens producing, within 30 min of administration, a stimulating effect that continues for at least 4-6 h. The active principles of the three plants that exhibit single dose stimulating effects are glycosides of phenylpropane- and phenylethane-based phenolic compounds such as salidroside, rosavin, syringin and triandrin, the latter being the most active.

Coordinating stomatal and xylem functioning – an evolutionary perspective

Coordinating stomatal and xylem functioning – an evolutionary perspective

Emerging and reemerging diseases: a health problem in the Americas

In the Region of the Americas the emerging and reemerging infectious diseases that had the greatest impact on health, in terms of their incidence and the number of deaths that they caused during the five-year period of 1999-2003, were: malaria, yellow fever, dengue hemorrhagic fever, AIDS, anthrax, and SARS, as well as infection by hantavirus and by West Nile virus. The appearance of epidemics of emerging and reemerging diseases is related to biological, social, and economic factors. Growth in international trade, the movement of large numbers of people across national borders, the variability and genetic adaptability of the causative microorganisms, and inefficiencies in public health systems help to spread infections and epidemics. To avoid or reduce the serious effects of these epidemics, countries should give priority in their national agendas to surveillance of emerging and reemerging diseases and should implement a set of measures to combat the diseases. The most important of these measures is to develop a strategy that is based on early warning and rapid response mechanisms, with personnel and laboratories as well as communications networks that link laboratories with health service providers. This strategy should be backed by priority funding and adequate policies.

Copper-induced oxidative stress in Saccharomyces cerevisiae targets enzymes of the glycolytic pathway

Increased cellular levels of reactive oxygen species are known to arise during exposure of organisms to elevated metal concentrations, but the consequences for cells in the context of metal toxicity are poorly characterized. Using two-dimensional gel electrophoresis, combined with immunodetection of protein carbonyls, we report here that exposure of the yeast Saccharomyces cerevisiae to copper causes a marked increase in cellular protein carbonyl levels, indicative of oxidative protein damage. The response was time dependent, with total-protein oxidation peaking approximately 15 min after the onset of copper treatment. Moreover, this oxidative damage was not evenly distributed among the expressed proteins of the cell. Rather, in a similar manner to peroxide-induced oxidative stress, copper-dependent protein carbonylation appeared to target glycolytic pathway and related enzymes, as well as heat shock proteins. Oxidative targeting of these and other enzymes was isoform-specific and, in most cases, was also associated with a decline in the proteins’ relative abundance. Our results are consistent with a model in which copper-induced oxidative stress disables the flow of carbon through the preferred glycolytic pathway, and promotes the production of glucose-equivalents within the pentose phosphate pathway. Such re-routing of the metabolic flux may serve as a rapid-response mechanism to help cells counter the damaging effects of copper-induced oxidative stress.