Oxygen–Glucose Deprivation (OGD) Modulates the Unfolded Protein Response (UPR) and Inflicts Autophagy in a PC12 Hypoxia Cell Line Model

Hypoxia is the lack of sufficient oxygenation of tissue, imposing severe stress upon cells. It is a major feature of many pathological conditions such as stroke, traumatic brain injury, cerebral hemorrhage, perinatal asphyxia and can lead to cell death due to energy depletion and increased free radical generation. The present study investigates the effect of hypoxia on the unfolded protein response of the cell (UPR), utilizing a 16-h oxygen–glucose deprivation protocol (OGD) in a PC12 cell line model. Expression of glucose-regulated protein 78 (GRP78) and glucose-regulated protein 94 (GRP94), key players of the UPR, was studied along with the expression of glucose-regulated protein 75 (GRP75), heat shock cognate 70 (HSC70), and glyceraldehyde 3-phosphate dehydrogenase, all with respect to the cell death mechanism(s). Cells subjected to OGD displayed upregulation of GRP78 and GRP94 and concurrent downregulation of GRP75. These findings were accompanied with minimal apoptotic cell death and induction of autophagy. The above observation warrants further investigation to elucidate whether autophagy acts as a pro-survival mechanism that upon severe and prolonged hypoxia acts as a concerted cell response leading to cell death. In our OGD model, hypoxia modulates UPR and induces autophagy.     

Corbicula (Bivalvia: Sphaeriacea) vs. Indigenous Mussels (Bivalvia: Unionacea) in U.S. Rivers: A Hard Case for Interspecific Competition?

At a time when populations of indigenous river mussels havebeen dwindling and/or disappearing, the introduced Asian clam,Corbicula, has spread through many U.S. rivers from Californiato Florida. In the Arkansas River Navigation System, a heavilymanaged waterway, Corbicula presently has a different "competitive"presence than it does in the relatively unmanaged Buffalo Riverin Arkansas. Comparative studies of both Corbicula and indigenousbivalved mollusks reveal biological bases for the contrastingkinds of benthic faunal change. There are ecologically relevant,distinctive differences between the two kinds of animals: inmantle/shell and mantle/gill apparatus, in the reproductivecomplex and neuroanatomy, and in spawning and locomotor behaviors.It is argued that the conservative molluscan characteristicsof Corbicula enable it to function in an exclusive, "contradictory"role with indigenous bivalves in a heavily managed waterway,and in a "contrary" competitive role elsewhere. Rationale ispresented for incorporating organismic evaluation into studiesof competition between distantly related taxa.     

Does the Fractionalization of Daily Physical Activity (Sporadic vs. Bouts) Impact Cardiometabolic Risk Factors in Children and Youth?

Objective

Children and youth accumulate their daily moderate-to-vigorous physical activity (MVPA) in bouts (i.e., ≥5 consecutive minutes) and in a sporadic manner (i.e., <5 consecutive minutes). The study objective was to determine, within children and youth, whether MVPA accumulated in bouts is more strongly associated with cardiometabolic risk factors than an equivalent volume of MVPA accumulated sporadically.

Methods

Participants consisted of 2754 children and youth aged 6–19 years from the 2003–2006 National Health and Nutrition Examination Survey, a representative cross-sectional study. Bouts and sporadic MVPA were measured objectively over 7 days using Actigraph accelerometers. Thresholds of 5 and 10 consecutive minutes were used to differentiate between bouts and sporadic MVPA. A high cardiometabolic risk factor score (CRS) was created based on measures of waist circumference, non-high-density lipoprotein cholesterol, C-reactive protein, and systolic blood pressure. Associations were examined using logistic regression and controlled for covariates (sex, age, ethnicity, socioeconomic status, dietary fat and sodium, smoking, and accelerometry wear time).

Results

The odds of a high CRS decreased in a dose-response for both the sporadic and bout MVPA measures. Relative to quartile 1, the odds ratio (95% confidence interval) for a high CRS in quartile 4 was 0.25 (0.10–0.60) for sporadic MVPA, 0.17 (0.09–0.34) for ≥5 minute bouts of MVPA, and 0.19 (0.11–0.34) for ≥10 minute bouts of MVPA. The sporadic and bout MVPA measures had a similar ability to distinguish between participants with high and normal CRS. Relative to 0 minutes of MVPA, an equivalent number of minutes of sporadic MVPA and bouts of MVPA had an almost identical odds ratio for a high CRS. The findings were consistent for 5 and 10 minute bout thresholds.

Conclusions

The relations between sporadic MVPA and bouts of MVPA with cardiometabolic risk factors were remarkably similar in children and youth.     

Is there a future for wild grapevine (Vitis vinifera subsp. silvestris) in the Rhine Valley?

The wild grapevine, Vitis vinifera L. subsp. silvestris (Gmelin) Hegi, is considered to be an endangered taxon in Europe, mainly as a consequence of the introduction of pathogens from North America and of the destruction of its habitat. In the Rhine Valley, nearly all populations disappeared due to river management, the intensi.cation of forestry, and the introduction of phylloxera. After a growing awareness of the need to preserve endangered forest ecosystems, attempts to reintroduce wild grapevine in the Rhine Valley were performed, particularly in the French nature reserves Erstein and Offendorf since 1992. However, regular surveys of the plants indicate the rapid decline of the populations. In 2002, we proposed to summarise the knowledge accumulated after 10 years of experiments. Results indicate that from the initial 91 individuals planted in 1992, only 14 survived in 2002 (2 in Erstein, 12 in Offendorf). The failure of the experiment may be explained by several factors: unsuitable sites (too shady, absence of support for the young plants), absence of monitoring, vandalism or predation. According to these results and recent knowledge of the ecology of the plant and of vines in general, new transplantation experiments are proposed in which the plants will be monitored during their establishment in the forests. The success of this second transplant (50 plants per reserve) will be enhanced by restoration projects of the Rhine River dynamics, with partial re-.ooding. Floods should help to avoid, or at least to reduce, pest and disease expansion on future adult plants.     

Selective Inhibition of K+, Na+, Cl?, and PO43? Uptake in Zea mays L. by Bipolaris (Helminthosporium) maydis Race T Pathotoxin: Evidence for a Plasmalemma Target Site? 1

Pathotoxin preparations were obtained from either axenic culture filtrate of race T of Bipolaris maydis (Nisikado) Shoemaker (new culture media and toxin purification procedures are described) or extracts of maize leaves infected with the fungus. The toxins (10(-6) to 10(-8)m) caused inhibition of [(86)Rb]K(+) uptake in leaf discs and apical root segments of Zea mays L. cv W64A Texas (Tcms) and normal (N) cytoplasms. Significant inhibition was measurable as early as 5 min after adding toxin. In Tcms per cent inhibition was increased by increasing toxin concentration and time in toxin, by using solution at pH 5 rather than pH 7, by decreasing external KCl concentration over the range 50 to 0.1 mm (in the presence of 0.5 mm CaSO(4)), or by exposing leaf discs to light rather than dark during the uptake period in toxin. Root uptake of (22)Na(+) and (36)Cl(-) was inhibited to a lesser extent than K(+). Inhibition of (32)PO(4) (3-) uptake occurred after 40 min when cyclosis had ceased.When combined with data in the literature, our data indicate that the plasmalemma is the probable primary site of toxin action in N and Tcms maize. Comparison of the effects of toxin on K(+) uptake in N and Tcms maize suggests the existence of more than one mode of toxin action: a weak disruptive effect in N and Tcms, and in addition, specific membrane sites in Tcms involved in monovalent ion uptake.Six genotypes in N or Tcms cytoplasm which exhibited different degrees of disease susceptibility in the field showed a corresponding gradation of susceptibility to the toxin when a K(+) uptake bioassay was used. This correlation is strong evidence that the sites of toxin action affecting K(+) transport have characteristics closely related to cellular factors regulating susceptibility to fungal attack.     

Testate Amoebae (Arcellinida and Euglyphida) vs. Ericoid Mycorrhizal and DSE Fungi: A Possible Novel Interaction in the Mycorrhizosphere of Ericaceous Plants?

Common occurrence of testate amoebae (TA) in the rhizosphere of mycorrhizal plants indicates existence of yet undocumented ecological interactions, involving three distinct groups of organisms: soil protists, mycorrhizal fungi, and their host plants. This tripartite relationship was to date investigated only to a limited extent, despite its probable importance for processes taking place in the mycorrhizosphere. In this study, we (1) explored spectra of different TA genera naturally associated with the rhizoplane of three autochthonous European Rhododendron species, (2) screened natural fungal colonization of the TA shells occupying the rhizoplane of selected rhododendrons, and (3) carried out two in vitro experiments addressing the question whether TA shells may serve as a nutrient source for ericoid mycorrhizal fungi (ErMF) and dark septate endophytes (DSE). Our field observations indicated that TA regularly associated with the rhizoplane of all screened rhododendrons and that ErMF and/or DSE associated with their roots possibly exploited the TA shells as a nutrient source. We were unable to detect any major differences among the TA spectra from the rhizoplanes with respect to the three Rhododendron species. The spectra were dominated by Diplochlamys, Centropyxis, Cyclopyxis, Euglypha, Trinema, and Assulina. Positive, neutral, and negative associations were found for various TA genera × Rhododendron species combinations. The highest fungal colonization was observed in Centropyxidae and Trigonopyxidae, reaching up to 45% of the shells in the case of Trigonopyxis. In the in vitro experiments, both ErMF Rhizoscyphus ericae and DSE Phialocephala fortinii regularly colonized TA shells, utilizing them as a source of nutrients. We hypothesize a complex relationship between ErMF–DSE and TA. If corroborated, it would represent an interesting nutrient loop in the mycorrhizosphere of ericaceous plants.     

The staminal lever mechanism in Salvia L. (Lamiaceae): a key innovation for adaptive radiation?

Floral key innovations play a significant role in the discussion of adaptive radiation in plants. The paper brings together a brief review of morphological key innovations in plants, elucidating their evolutionary significance in flower–pollinator interactions, and new data on Salvia, a genus being examined as an example for presumed adaptive radiation. We hypothesize that the characteristic staminal lever mechanism functions as a key innovation. It is defined as a functional unit including the modification of stamens to lever-like structures, their reversible movement, and the organization of the remaining floral structures involved in the process of pollen transfer. We follow the assumption that structure and functioning of the staminal levers play a major role in the process of pollen deposition on the pollinator's body, and that minute changes of both their proportions and their interactions with pollinators may have significant consequences for the pollination system. The functioning of the staminal lever mechanism is tested by field investigations, biomechanical experiments and pollination simulations. First results are presented, and possible modes of allopatric and sympatric speciation are discussed, based on morphometry of Salvia flowers and pollinators as well as on the operating mode of the staminal lever mechanism. Special attention is given to species-specific patterns of pollen deposition on the pollinator's body. We assume that, depending on the precision of the lever movement, sympatric Salvia species flowering during overlapping periods and sharing the same pollinating species may be either mechanically isolated from each other or able to hybridize. The latter may result in speciation, as may spontaneous mutations influencing the flower-pollinator interaction, e.g. by significant changes in morphometry of the staminal lever system and/or other flower structures. As a consequence, Salvia individuals may deposit pollen on a different part of the pollinator's body, or even adapt to a new pollinator species, both resulting in reproductive isolation from the parental population.     

Thermal sensitivity of juvenile rabbitfishes Siganus doliatus and S. lineatus (Siganidae): a key role for habitat?

The majority of our understanding of the effects of climate change on coral reef fishes are currently based on studies of small-bodied species such as damselfishes. By contrast, we know little about the potential impacts of ocean warming on larger species of herbivorous and detritivorous reef fish, despite them being a critical functional group and an essential source of food protein for millions of people. In addition, we know little of the role of habitat in determining species’ thermal sensitivity and the legitimacy of extrapolating thermal performance across closely-related species from different habitat types. Here we test the effect of exposure to increased water temperature during juvenile development on key physiological and behavioral traits of two species of rabbitfish typically associated with different habitats: Siganus doliatus (reef-associated) and S. lineatus (estuarine). Wild-caught juveniles were reared for 14 weeks at temperatures representing present-day ambient conditions (28.0 °C), late-summer ambient conditions (30.0 °C), or those projected on reefs under future global warming scenarios (31.5 °C). We then measured the somatic (growth, condition, immune response) and behavioral (feeding rate, latency to feed and activity level) traits of individuals within each treatment to determine the sensitivity of each species to elevated water temperatures. Overall, both species showed comparatively robust levels of thermal tolerance, based on previously-documented responses of small-bodied reef fishes. However, two very different patterns emerged. The reef-associated S. doliatus showed a greater physiological response to temperature, with negative effects on hepatosomatic condition and immune function observed in individuals exposed to the 31.5 °C treatment. By contrast, there were no negative physiological effects of temperature observed in S. lineatus and instead we recorded behavioral changes, with individuals at 30 °C and 31.5 °C displaying altered feeding behavior (increased feeding rate and decreased latency to feed). These distinct responses observed between congeners are likely due to their evolutionary history and flag the potential inaccuracies that could arise from extrapolating effects of ocean warming across even closely-related species adapted to different habitats.

     

The KCNH2 Genetic Polymorphism (1956, C>T) Is a Novel Biomarker That Is Associated with CCB and α,β-ADR Blocker Response in EH Patients in China

Background

KCNH2 (hERG) potassium channels have an integral role in regulating the excitability of smooth muscle cells. Some pathways driven by angiotensin II, nitric oxide and adrenergic receptors blocker are involved in modulating the properties of KCNH2 potassium channels. And these pathways are closely related to blood pressure regulation. Therefore, we hypothesized that KCNH2 genetic polymorphisms may affect blood pressure response to the antihypertensive drug therapies.

Materials and Methods

To evaluate the interactions between KCNH2 genetic polymorphisms and individual blood pressure response to antihypertensive drugs, 370 subjects with essential hypertension (EH) were studied. In evaluating the interactions between KCNH2 genetic polymorphisms and drug response to blood pressure, multivariable ANOVA analysis followed by Bonferroni correction were carried out.

Results

There were statistically significant interactions between KCNH2 (1956, C>T) polymorphism and DBP change (P = 0.010), MAP change (P = 0.014) on azelnidipine or nitrendipine therapy patients at the end of 6 weeks. We found that the KCNH2 (1956,C>T) polymorphism was associated with the hypotensive effects of α,β-ADR blockers of DBP change at the end of 4 and 6 weeks'' treatment in an age- and gender-dependent manner (P = 0.007 and 0.019, respectively). Similar results were also observed for changes in MAP at the end of 4 and 6 weeks (P-values were 0.035 and 0.078, respectively). While patients who received imidapril, candesartan and irbesartan therapy, no significant difference in drug response among KCNH2(1956,C>T) genotype was observed.

Conclusion

We have reported for the first time that KCNH2 (1956, C>T) polymorphism is associated with efficacy of antihypertensive drugs CCBs and ADR blockers, and may serve as a novel biomarker for individualized therapy for certain antihypertensive drugs.     

Parasites in sexual and asexual mollies (Poecilia, Poeciliidae, Teleostei): a case for the Red Queen?

The maintenance of sexual reproduction in the face of its supposed costs is a major paradox in evolutionary biology. The Red Queen hypothesis, which states that sex is an adaptation to fast-evolving parasites, is currently one of the most recognized explanations for the ubiquity of sex and predicts that asexual lineages should suffer from a higher parasite load if they coexist with closely related sexuals. We tested this prediction using four populations of the sexual fish species Poecilia latipinna and its asexual relative Poecilia formosa. Contrary to expectation, no differences in parasite load could be detected between the two species.     

Nitric oxide (NO) traffic in endothelial NO synthase. Evidence for a new NO binding site dependent on tetrahydrobiopterin?

Nitric oxide (NO) traffic within the reduced ferrous-nitrosyl complex of endothelial nitric-oxide synthase (eNOS) has been studied by ultrafast time-resolved absorption spectroscopy. In the presence of tetrahydrobiopterin, the rate of NO rebinding to the heme upon photodissociation depends on the NO concentration. The time scale of this process, picoseconds to nanoseconds, precludes a diffusion from the solution toward the protein medium, and altogether the data point at a new NO binding site within the protein. Comparison of the kinetics of pterin-bound and -depleted eNOS points out that the existence of this new site depends on the presence of tetrahydrobiopterin. The new non-heme site may act as a "doorstep" to the heme pocket and control NO escape from eNOS.     

Hybridization and crossability in Caiophora (Loasaceae subfam. Loasoideae): Are interfertile species and inbred populations results of a recent radiation?

Interspecific hybridization is considered a possible mechanism of plant diversification. The Andes are a hotspot of biodiversity, but hybridization in Andean taxa has so far not been investigated intensively. The current study investigates crossability in Caiophora (Loasaceae subfam. Loasoideae) by experimental interspecific hybridization of seven different species. Hand pollination was undertaken, developing fruits counted, thousand (seed) grain weights, and seed viability were examined. Cross pollination led to some fruit set in 36 of the 37 different combinations. Overall fruit set was virtually identical irrespective of the combination of parental plants. Mean germination rates were much higher in hybrid seeds, indicating a marked heterosis effect and the possible presence of an inbreeding depression in the source populations: In experimental hybridization the divergent taxa of Caiophora behave like isolated, inbred populations of a single species. Allopatry and different habitat preferences seem to be the key factors keeping the (interfertile) taxa of Caiophora apart in the apparent absence of both postmating isolating mechanisms and obvious isolating mechanisms in phenology and floral biology. Interspecific hybrids reported from the wild appear to be the result of secondary contact due to human impact.     

Indication for ‘Over the Scope’ (OTS)-Clip vs. Covered Self-Expanding Metal Stent (cSEMS) Is Unequal in Upper Gastrointestinal Leakage: Results from a Retrospective Head-to-Head Comparison

Background

Intestinal perforation or leakage increases morbidity and mortality of surgical and endoscopic interventions. We identified criteria for use of full-covered, extractable self-expanding metal stents (cSEMS) vs. ‘Over the scope’-clips (OTSC) for leak closure.

Methods

Patients who underwent endoscopic treatment for postoperative leakage, endoscopic perforation, or spontaneous rupture of the upper gastrointestinal tract between 2006 and 2013 were identified at four tertiary endoscopic centers. Technical success, outcome (e.g. duration of hospitalization, in-hospital mortality), and complications were assessed and analyzed with respect to etiology, size and location of leakage.

Results

Of 106 patients (male: 75 (71%), female: 31 (29%); age (mean ± SD): 62.5 ± 1.3 years, 72 (69%) were treated by cSEMS and 34 (31%) by OTSC. For cSEMS vs. OTSC, mean treatment duration was 41.1 vs. 25 days, p<0.001, leakage size 10 (1-50) vs. 5 (1-30) mm (median (range)), and complications were observed in 68% vs. 8.8%, p<0.001, respectively. Clinical success for primary interventional treatment was observed in 29/72 (40%) vs. 24/34 (70%, p = 0.006), and clinical success at the end of follow-up was 46/72 (64%) vs. 29/34 (85%) for patients treated by cSEMS vs. OTSC; p = 0.04.

Conclusion

OTSC is preferred in small-sized lesions and in perforation caused by endoscopic interventions, cSEMS in patients with concomitant local infection or abscess. cSEMS is associated with a higher frequency of complications. Therefore, OTSC might be preferred if technically feasible. Indication criteria for cSEMS vs. OTSC vary and might impede design of randomized studies.     

Evolution and diversification of Group 1 [NiFe] hydrogenases. Is there a phylogenetic marker for O(2)-tolerance?

Group 1 hydrogenases are periplasmic enzymes and are thus strongly affected by the "outside world" the cell experiences. This exposure has brought about an extensive heterogeneity in their cofactors and redox partners. Whereas in their majority they are very O(2)-sensitive, several enzymes of this group have been recently reported to be O(2)-tolerant. Structural and biochemical studies have shown that this O(2)-tolerance is conferred by the presence of an unusual iron-sulfur cofactor with supernumerary cysteine ligation (6 instead of 4 Cys, hence called '6C cluster'). This atypical cluster coordination affords redox plasticity (i.e. two-redox transitions), unprecedented for this type of cofactors and likely involved in resistance to O(2). Genomic screening and phylogenetic tree reconstruction revealed that 6C hydrogenases form a monophyletic clade and are unexpectedly widespread among bacteria. However, several other well-defined clades are observed, which indicate early diversification of the enzyme into different subfamilies. The various idiosyncrasies thereof are shown to comply with a very simple rule: phylogenetic grouping of hydrogenases directly correlates with their specific functions and hence biochemical characteristics. The observed variability results from gene duplication, gene shuffling and subsequent adaptation of the diversified enzymes to specific environments. An important factor for this diversification seems to have been the emergence of molecular oxygen. Hydrogenases appear to have dealt with oxidative stress in various ways, the most successful of which, however, was the innovation of the 6C-cluster conferring pronounced O(2)-tolerance to the parent enzymes.     

Response of maritime pine (Pinus?pinaster Ait.) recruitment to fire severity and post-fire management in a coastal burned area in Galicia (NW Spain)

The short-term effects of fire severity and post-fire management on maritime pine recruitment were evaluated in a mature serotinous pine stand in a coastal area of Galicia (NW Spain) burned by a wildfire occurred in the summer of 2001. Two levels of fire severity estimated by the levels of tree crown damage—scorched and unaffected crown—were compared. Seed dispersal and first cohort pine (November 2001) seedling density, before salvage logging, were significantly and positively affected by fire severity. Between November and January, a fungal attack caused a noticeable decrease in seedling density in both levels of fire severity. The first cohort survival was significantly reduced by harvesting and slash treatments carried out in February 2002. However, slash chopping favoured a new pine cohort, particularly in the unaffected crown plots, in which seedling density was significantly higher than in the scorched crown plots between July 2002 and February 2003. First cohort seedling survival and height were positively related. Fire severity levels, combined with post fire management, did not appear to determine final pine seedling density and height. Finally, reduction in seedling density caused by post-fire management did not threaten pine establishment and may reduce the need for subsequent thinning operations.     

Call divergence is correlated with geographic and genetic distance in greenish warblers (Phylloscopus trochiloides): a strong role for stochasticity in signal evolution?

Divergence in signalling systems might play a central role in speciation. To assess the importance of possible causes of signal divergence, we examine two types of vocalizations within a geographically variable species complex, the greenish warblers (Phylloscopus trochiloides Sundevall). Calls, which are used by both sexes throughout the year, and songs, which are sung primarily by breeding males, differ distinctly between two distinct Siberian forms. Through a ring of southern populations that connect the northern forms, signal divergence is correlated with both geographic distance and genetic divergence. Calls and songs differ in their particular patterns of geographic variation, probably because of the larger influence of sexual selection on songs than on calls. These patterns are supportive of neither acoustic adaptation nor morphology being major drivers of divergence in vocalizations. Rather, these results support the importance of stochastic evolution of communication systems in the evolution of new species.