What Happened to <Emphasis Type="Italic">Nezara viridula</Emphasis> (L.) in the Americas? Possible Reasons to Explain Populations Decline

Once abundant in the Americas, the southern green stink bug Nezara viridula (L.) has gradually declined in numbers. Until the 1990s, it was considered the main pest of major crops such as soybean, Glycine max (L.) Merrill, particularly in southern Brazil and southern USA, as well as Argentina, Uruguay, and other countries. In the past 15+ years, a dramatic population decrease was observed to the point of now being considered a secondary pest in these referred countries. In this article, we list and discuss possible reasons which explain the decline in N. viridula population in the Americas. These factors include the following: (1) the steady increase of herbicides used in no-tillage/multiple cropping systems affecting potential hosts such as weeds in crop fields and nearby natural vegetation; (2) the change in cultivation systems, mostly in the Neotropics, favoring other species more adapted to exploit crops in modern day agriculture; (3) competition among several species of stink bugs that colonize major crops; (4) the growing impact of several species of egg parasitoids, some of them laboratory reared and released in crop fields, and other natural enemies (parasitoids and predators); and (5) the impact of global climate change affecting its distribution and biology.     

TNFalpha-induced AMPA-receptor trafficking in CNS neurons; relevance to excitotoxicity?

Injury and disease in the CNS increases the amount of tumor necrosis factor alpha (TNFalpha) that neurons are exposed to. This cytokine is central to the inflammatory response that occurs after injury and during prolonged CNS disease, and contributes to the process of neuronal cell death. Previous studies have addressed how long-term apoptotic-signaling pathways that are initiated by TNFalpha might influence these processes, but the effects of inflammation on neurons and synaptic function in the timescale of minutes after exposure are largely unexplored. Our published studies examining the effect of TNFalpha on trafficking of AMPA-type glutamate receptors (AMPARs) in hippocampal neurons demonstrate that glial-derived TNFalpha causes a rapid (<15 minute) increase in the number of neuronal, surface-localized, synaptic AMPARs leading to an increase in synaptic strength. This indicates that TNFalpha-signal transduction acts to facilitate increased surface localization of AMPARs from internal postsynaptic stores. Importantly, an excess of surface localized AMPARs might predispose the neuron to glutamate-mediated excitotoxicity and excessive intracellular calcium concentrations, leading to cell death. This suggests a new mechanism for excitotoxic TNFalpha-induced neuronal death that is initiated minutes after neurons are exposed to the products of the inflammatory response. Here we review the importance of AMPAR trafficking in normal neuronal function and how abnormalities that are mediated by glial-derived cytokines such as TNFalpha can be central in causing neuronal disorders. We have further investigated the effects of TNFalpha on different neuronal cell types and present new data from cortical and hippocampal neurons in culture. Finally, we have expanded our investigation of the temporal profile of the action of this cytokine relevant to neuronal damage. We conclude that TNFalpha-mediated effects on AMPAR trafficking are common in diverse neuronal cell types and very rapid in their onset. The abnormal AMPAR trafficking elicited by TNFalpha might present a novel target to aid the development of new neuroprotective drugs.     

Duetting—A mechanism to strengthen pair bonds in a dispersed pair‐living primate (Lepilemur edwardsi)?

Duetting is defined as an interactively organized pair display in which one pair partner coordinates its vocalizations in time with those of the other. It is widespread among tropical birds and cohesive pair‐living primates, in which it is suggested to strengthen pair bonds. We know very little about the presence and function of duetting in dispersed pair‐living mammals. We studied duetting behavior in a solitary foraging, but pair‐sleeping, primate, the Milne Edwards' sportive lemur, in a dry deciduous forest of north‐western Madagascar. We radio‐tracked six pairs throughout 1 year and recorded their sleeping sites and associations, home‐range use, and vocal and behavioral interactions. Three different periods were covered (mating, pregnancy, and offspring care). Sleeping partners form long‐term pair bonds, indicated by an almost exclusive pair‐specific usage of sleeping sites and home‐ranges across periods. We explored three functional hypothesis of duetting: mate reunion, pair reunion, and joint‐territorial defense. Pairs regularly engaged in duet calling. Duetting increased significantly during the offspring care period. Duetting occurred significantly more often at feeding sites than at sleeping sites. Pair partners synchronized behavioral activities after duetting. The activity most often synchronized was locomotion. Pair partners played an equal role in duetting with no difference between sexes in starting or terminating duetting. Altogether, our results provide support for the hypothesis that in dispersed pair‐living primates, duetting evolved as a mechanism to coordinate activities between pair partners dispersed in space, to strengthen pair bonds, and, perhaps, to limit infanticide and nutritional stress in lactating females. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.     

Gα<Subscript>13</Subscript> is closely related to hematopoiesis in zebrafish

Heterotrimeric guanine nucleotide-binding regulatory proteins (G proteins) function as signal transducers and control many different physiologic processes. G proteins can be grouped into four families: G_s, G_i, G_q and G₁₂. Gα₁₃ belongs to the G₁₂ family. In zebrafish, there are two isoforms of Gα₁₃: Gα₁₃a and Gα₁₃b. We show here that knockdown of Gα₁₃b in zebrafish results in hematopoietic and angiogenic defects. The Gα₁₃b morphants don’t show complete loss of expression of gata1, pu.1 or flk until 35 hpf suggests that Gα₁₃b is closely related to the development of hematopoietic cells. Further studies reveal that blood cells and vascular endothelial cells have undergone apoptosis through a p53-dependent pathway in Gα₁₃b-depleted embryos. Injection of p53 morpholino could partially rescue the phenotype of Gα₁₃b morphants. These data possibly demonstrate a new role for Gα₁₃ in cell survival.     

Freeze–thaw induced genotoxicity in buffalo (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) spermatozoa in relation to total antioxidant status

Use of cryopreserved semen has become an important tool in assisted reproduction but freezing and thawing cause sub-lethal damage to spermatozoa. This is detrimental to sperm because of the membrane damage including permeability and integrity. An excess generation of reactive oxygen species (ROS) creates oxidative stress due to reduced antioxidant status of the cryopreserved spermatozoa. In the present study fresh buffalo semen was collected and divided into two aliquots. One aliquot was used for fresh semen analysis and the other was cryopreserved in Tris-egg yolk-citrate extender. The semen samples were used to study different sperm quality parameters like motility, viability, membrane integrity and total antioxidant status. The DNA integrity in fresh and cryopreserved spermatozoa was also studied using comet assay. The sperm quality parameters like post-thaw sperm motility, viability, membrane integrity and total antioxidant status of cryopreserved spermatozoa were significantly lowered (P < 0.05) compared to fresh spermatozoa. The DNA fragmentation in cryopreserved spermatozoa was significantly higher (P < 0.01) as compared to fresh spermatozoa. The results show that the irreversible DNA damage occurs in spermatozoa during cryopreservation.     

Elastic energy storage in β-sheets with application to F<Subscript>1</Subscript>-ATPase

We present a methodology for obtaining the elastic properties of protein motifs. We combine the use of interpolated structures (IS), molecular dynamics (MD) and collective coordinates to deduce the elastic properties of the -sheet in F₁ ATPase. We find that about 3.5 kcal/mol (6 k_BT at room temperature) of elastic energy is stored in the -sheet as the -subunit undergoes its hinge bending motion, in good agreement with the finite element model of Wang and Oster [Nature (1998) 396:279–282]. The technique should be useful for -sheets in other proteins and aid in the construction of phenomenological models for molecular motors that are computationally prohibitive for MD alone.     

Current developments in groundwater ecology — from biodiversity to ecosystem function and services

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Physiological and growth responses to water deficits in cultivated strawberry (Fragaria × ananassa) and in one of its progenitors,Fragaria chiloensis

Cultivation of strawberry (Fragaria × ananassa) requires irrigation. Improving crop water use efficiency (WUE) is important for future production. Fragaria chiloensis, a progenitor of cultivated strawberry, grows in sandy soils, and may prove useful in breeding for improved WUE. Little, however, is known about variation in drought tolerance within this species. This research explores drought tolerance in a range of F. chiloensis and F. × ananassa genotypes. Four cultivars of F. × ananassa and four accessions of F. chiloensis were compared when well watered, and when subjected to a water deficit (65% of evapotranspiration). New leaf production, stomatal conductance, and photosynthetic rate were significantly reduced under water deficit, and also significantly differed between genotypes. A significant interaction of genotype and irrigation was found for transpiration rate, leaf area and dry mass, production of runners, predawn water potential, a measure of transpiration efficiency (shoot biomass produced per litre water transpired), and carbon isotope composition, indicating that some genotypes were more severely affected by water deficit than others. The South American F. chiloensis accession ‘Manzanar Alto’ had a similar rate of transpiration to the commercial cultivars, but the remaining (North American) F. chiloensis accessions used far less water than the F. × ananassa. Well-watered F. chiloensis plants used less water than water-limited plants of the F. × ananassa cultivar ‘Florence’. Transpiration efficiency of the F. chiloensis accession ‘BSP14’ was improved by water deficit: this was the only genotype not to show a reduction in leaf area and dry mass under water deficit. Greater drought resistance in three F. chiloensis accessions compared to F. × ananassa results from a conservative vegetative growth strategy, reducing loss of water.     

Retracted: Tusk shells in trouble? Physiology and behavior in response to changing temperature in a scaphopod (Mollusca: Scaphopoda: Dentaliida)

Scaphopods (tusk shells) are infaunal marine predators that occur at locally high densities in coastal and deep‐sea mud habitats, and as consumers of foraminifera they are important in carbon cycling. We investigated oxygen metabolism and burying behavior of the scaphopod Rhabdus rectius and its responses to altered temperatures. These are the first measurements of oxygen uptake rates for any member of this taxonomic class. In response to elevated temperatures, oxygen uptake rates increased, but the ability of animals to bury themselves in sediment was compromised. Female scaphopods were significantly larger than males and, when corrected for body mass, oxygen uptake rates were consistently higher for female individuals than for males. This is consistent with previous anecdotal observations of females in other scaphopod species being larger and potentially more active. In conditions of declining oxygen availability, individuals of Rhabdus rectius showed strong oxyregulatory ability by maintaining the same oxygen uptake rate displayed in normoxic conditions. The ability to maintain normal metabolic functioning even in conditions of oxygen limitation would benefit a species living in a benthic environment that may be prone to temporary or transient anoxic events. Yet the decrease in normal escape response in moderately elevated temperatures indicates these animals may be at risk from rising sea temperatures.     

IF<Subscript>1</Subscript> distribution in HepG2 cells in relation to ecto–F<Subscript>0</Subscript>F<Subscript>1</Subscript>ATPsynthase and calmodulin

F₀F₁ATPsynthase is now known to be expressed as a plasma membrane receptor for several extracellular ligands. On hepatocytes, ecto–F₀F₁ATPsynthase binds apoA–I and triggers HDL endocytosis concomitant with ATP hydrolysis. Considering that inhibitor protein IF₁ was shown to regulate the hydrolytic activity of ecto–F₀F₁ATPsynthase and to interact with calmodulin (CaM) in vitro, we investigated the subcellular distributions of IF₁, calmodulin (CaM), OSCP and β subunits of F₀F₁ATPsynthase in HepG2 cells. Using immunofluorescence and Western blotting, we found that around 50% of total cellular IF₁ is localized outside mitochondria, a relevant amount of which is associated to the plasma membrane where we also found Ca²⁺–CaM, OSCP and β. Confocal microscopy showed that IF₁ colocalized with Ca²⁺–CaM on plasma membrane but not in mitochondria, suggesting that Ca²⁺–CaM may modulate the cell surface availability of IF₁ and thus its ability to inhibit ATP hydrolysis by ecto–F₀F₁ATPsynthase. These observations support a hypothesis that the IF₁–Ca²⁺–CaM complex, forming on plasma membrane, functions in the cellular regulation of HDL endocytosis by hepatocytes.     

Endogenous ABA content in relation to maturation of somatic embryos in <Emphasis Type="Italic">Tulip</Emphasis>a (L.) ‘Apeldoorn’ cultures

The aim of the present study was to estimate the endogenous abscisic acid (ABA) content in tulip ‘Apeldoorn’ torpedo and mature somatic embryos. Moreover, the effect of exogenous ABA and/or its inhibitor fluridone on somatic embryo maturation and conversion into plantlets was investigated. Torpedo-stage somatic embryos were subcultured on media containing 5 μM of picloram and 1 μM of 6-benzyl-aminopurine (BAP)—control, and combinations of ABA (0 or 10 μM) and/or fluridone (0 or 30 μM) for 1 week. Then, the torpedo embryos were transferred to a maturation medium containing 0.25 μM of α-naphthaleneacetic acid (NAA) and 2.5 μM of BAP, without ABA and fluridone treatment, and cultivated under darkness or light for ten weeks. Endogenous ABA content (first time measured in tulip somatic embryos) was evaluated by ELISA test. The obtained results revealed that the highest level of endogenous ABA, at 17.45 nmol g^?1 dry weight (DW), was recorded in torpedo-stage of tulip embryo development, only after 1 week of ABA treatment, and was nearly 10 times higher in comparison with the control. Simultaneous addition of ABA and fluridone to the medium resulted in the lowering of the ABA concentration to 9.58 nmol g^?1 DW. During ten weeks of maturation of the embryos, the endogenous ABA content in mature tissue of tulip somatic embryo considerably decreased to an amount 0.87–1.33 nmol g^?1 DW (irrespective of ABA and fluridone treatment) and did not differ significantly from control (0.59 nmol g^?1 DW). Exogenous ABA and fluridone significantly decreased the growth value of fresh weight (FW) of the tulip torpedo-shaped and mature embryos under light conditions. Percentage of the DW of the torpedo embryos treated with exogenous ABA was significantly higher (15.43–17.02) in comparison with the control (10.87). Three to three and a half times more malformed mature embryos were noted under light conditions than in darkness, irrespective of ABA and fluridone treatment. The highest percentage of mature embryos forming shoots (conversion) was observed under light conditions in the control and after fluridone treatment (26 and 20%, respectively).     

Is fecundity in plaice (Pleuronectes platessa L.) down‐regulated in response to reduced food intake during autumn?

The effect of controlling food intake during the autumn, which is the time of late vitellogenesis, on fecundity, atresia and follicle and ovary growth was examined for plaice Pleuronectes platessa . Eighteen fish were kept in individual pens and either fed on a high or low ration diet. Fish which increased in whole body condition exhibited an increase in carcass condition which means that when food intake is sufficient to maintain whole body condition some resources are used as storage. Follicle growth rate was positively correlated with change in Fulton's condition and total atresia was negatively correlated with change in Fulton's condition. Thus, the rate of vitellogenesis was dependent on the availability of an exogenous food source. Fecundity at the end of the experiment was positively correlated with mass and total length. Food intake had no effect on relative fecundity; however, fish which had a lower food intake lost mass and had a greater intensity of atresia, lowering their absolute fecundity. One fish in a very low condition at the start of the experiment skipped spawning and one fish exhibited a decrease in average follicle diameter during the experiment which is hypothesized to be a prelude to mass atresia.     

Temporal variation in δ<Superscript>13</Superscript>C of ecosystem respiration in the Pacific Northwest: links to moisture stress

We measured seasonal and interannual variations in delta(13)C values within the carbon reservoirs (leaves and soil) and CO(2) fluxes (soil and ecosystem respired CO(2)) of an old growth coniferous forest in the Pacific Northwest USA with relation to local meteorological conditions. There were significant intra-annual and interannual differences in the carbon isotope ratios of CO(2) respired at both the ecosystem (delta(13)C(R)) and the soil levels (delta(13)C(R-soil)), but only limited variations in the carbon isotope ratios of carbon stocks. The delta(13)C(R) values varied by as much as 4.4 per thousand over a growing season, while delta(13)C(R-soil )values changed as much as 6.2 per thousand. The delta(13)C of soil organic carbon (delta(13)C(SOC)) and needle organic carbon (delta(13)C(P)) exhibited little or no significant changes over the course of this study. Carbon isotope discrimination within leaves (Delta(p)) showed systematic decreases with increased canopy height, but remained fairly constant throughout the year (Delta(p)=17.9 per thousand -19.2 per thousand at the top of the canopy, Delta(p)=19.6 per thousand -20.9 per thousand at mid-canopy, Delta(p)=23.3 per thousand -25.1 per thousand at the canopy base). The temporal variation in the delta(13)C of soil and ecosystem respired CO(2) was correlated ( r=0.93, P<0.001) with soil moisture levels, with dry summer months having the most (13)C-enriched values. The dynamic seasonal changes in delta(13)C of respired CO(2) are hypothesized to be the result of fast cycling of recently fixed carbon back to the atmosphere. One scaling consequence of the seasonal and interannual variations in delta(13)C(R) is that inversion-based carbon-cycle models dependent on observed atmospheric CO(2) concentration and isotope values may be improved by incorporating dynamic delta(13)C(R) values to interpret regional carbon sink strength.     

Trends in 1-year survival of people admitted to hospital in Ontario, 1994–2009

Background:

Changes in the long-term survival of people admitted to hospital is unknown. This study examined trends in 1-year survival of patients admitted to hospital adjusted for improved survival in the general population.

Methods:

One-year survival after admission to hospital was determined for all adults admitted to hospital in Ontario in 1994, 1999, 2004, or 2009 by linking to vital statistics datasets. Annual survival in the general population was determined from life tables for Ontario.

Results:

Between 1994 and 2009, hospital use decreased (from 8.8% to 6.3% of the general adult population per year), whereas crude 1-year mortality among people with hospital admissions increased (from 9.2% to 11.6%). During this time, patients in hospital became significantly older (median age increased from 51 to 58 yr) and sicker (the proportion with a Charlson comorbidity index score of 0 decreased from 68.2% to 60.0%), and were more acutely ill on admission (elective admissions decreased from 47.4% to 42.0%; proportion brought to hospital by ambulance increased from 16.1% to 24.8%). Compared with 1994, the adjusted odds ratio (OR) for death at 1 year in 2009 was 0.78 (95% confidence interval [CI] 0.77–0.79). However, 1-year risk of death in the general population decreased by 24% during the same time. After adjusting for improved survival in the general population, risk of death at 1 year for people admitted to hospital remained significantly lower in 2009 than in 1994 (adjusted relative excess risk 0.81, 95% CI 0.80–0.82).

Interpretation:

After accounting for both the increased burden of patient sickness and improved survival in the general population, 1-year survival for people admitted to hospital increased significantly from 1994 to 2009. The reasons for this improvement cannot be determined from these data. Hospitals have a special place in most health care systems. Hospital staff care for the people with the most serious illnesses and the most vulnerable. They are frequently the location of many life-defining moments — including birth, surgery, acute medical illness and death — of many people and their families. Hospitals serve as a focus in the training of most physicians. In addition, they consume a considerable proportion of health care expenditures worldwide. ¹ Given the prominence of hospitals in health care systems, measuring outcomes related to hospital care is important. In particular, the measurement of trends for outcomes of hospital care can help us to infer whether the care provided to hospital patients is improving. Previous such studies have focused on survival trends for specific diseases or patients who received treatment in specific departments. ^{2 – 12} None of these studies have adjusted for survival trends in the general population, the adjustment for which is important to determine whether changes in survival of patients in hospital merely reflect changes in the overall population. In this study, whether or not patient outcomes have changed over time was determined by examining trends in 1-year survival in all patients admitted to hospital, adjusting for improved survival in the general population.     

Transition-metal-mediated uncaging in living human cells — an emerging alternative to photolabile protecting groups

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Monitoring Cl<Superscript>−</Superscript> Movement in Single Cells Exposed to Hypotonic Solution

Self-referencing ion - selective electrodes (ISEs), made with Chloride Ionophore I-Cocktail A (Fluka), were positioned 1–3 μm from human embryonic kidney cells (tsA201a) and used to record chloride flux during a sustained hyposmotic challenge. The ISE response was close to Nernstian when comparing potentials (V_N) measured in 100 and 10 mM NaCl (ΔV_N = 57 ± 2 mV), but was slightly greater than ideal when comparing 1 and 10 mm NaCl (ΔV_N = 70 ± 3 mV). The response was also linear in the presence of 1 mm glutamate, gluconate, or acetate, 10 μm tamoxifen, or 0.1, 1, or 10 mm HEPES at pH 7.0. The ISE was ∼3 orders of magnitude more selective for Cl⁻ over glutamate or gluconate but less than 2 orders of magnitude move selective for Cl⁻ over bicarbonate, acetate, citrate or thiosulfate. As a result this ISE is best described as an anion sensor. The ISE was ‘poisoned’ by 50 μm 5−nitro-2-(3phenylpropyl-amino)-benzoic acid (NPPB), but not by tamoxifen. An outward anion efflux was recorded from cells challenged with hypotonic (250 ± 5 mOsm) solution. The increase in efflux peaked 7–8 min before decreasing, consistent with regulatory volume decreases observed in separate experiments using a similar osmotic protocol. This anion efflux was blocked by 10 μm tamoxifen. These results establish the feasibility of using the modulation of electrochemical, anion-selective, electrodes to monitor anions and, in this case, chloride movement during volume regulatory events. The approach provides a real-time measure of anion movement during regulated volume decrease at the single-cell level.     

Differential Induction of β-1,3-Glucanase Gene in Expression of Partial Resistance to Rust (<Emphasis Type="Italic">Uromyces fabae</Emphasis> (Pers.) de-Bary) in Pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.)

The present study highlights differential induction of pathogenesis related protein PR-2 (β-1,3- glucanases) in expression of rust resistance in pea using different resistant and susceptible recombinant inbred lines of pea (Pisum sativum L.). The enhanced levels of glucanase expression was noted in resistant genotypes at 24 h post inoculations that was negatively correlated (–0.54) with Area Under Disease Progress Curve (AUDPC) and positively correlated (0.67) with lignin accumulations. A significant role of structural defence mechanism in rust resistance in pea was evident from reduced colony size and lesser number of haustorium per colony in resistant lines as well as their negative correlations with lignin accumulation and AUDPC. Gene specific markers indicated constitutive nature of glucanase and peroxidase genes in test genotypes, though differential expression of the glucanase activity was observed in the resistant and susceptible genotypes. However, association of peroxidases with resistance to pea rust is yet to be established due to its non-specific role in slow rusting in pea. The result showed a significant role of β-1,3-glucanase in expression of rust resistance in pea.