Reduced activity of juvenile hormone esterase in microsporidia-infected Lymantria dispar larvae

Infection of the fat body of Lymantria dispar (Lep.: Lymantriinae) larvae with the microsporidium Vairimorpha disparis has severe effects on juvenile hormone (JH) metabolism of the host. Beginning 8 days postinfection, activity of the JH degrading enzyme JH-esterase was significantly lower in the hemolymph of infected than uninfected larvae. Activity remained low as microsporidiosis progressed. JH titers were slightly elevated in infected larvae; the difference was not significant in most cases. This disturbance of JH metabolism may be due to generally impaired fat body functions and high demand for resources by the developing pathogen.     

SNF1-Related Protein Kinases Type 2 Are Involved in Plant Responses to Cadmium Stress

Cadmium ions are notorious environmental pollutants. To adapt to cadmium-induced deleterious effects plants have developed sophisticated defense mechanisms. However, the signaling pathways underlying the plant response to cadmium are still elusive. Our data demonstrate that SnRK2s (for SNF1-related protein kinase2) are transiently activated during cadmium exposure and are involved in the regulation of plant response to this stress. Analysis of tobacco (Nicotiana tabacum) Osmotic Stress-Activated Protein Kinase activity in tobacco Bright Yellow 2 cells indicates that reactive oxygen species (ROS) and nitric oxide, produced mainly via an l-arginine-dependent process, contribute to the kinase activation in response to cadmium. SnRK2.4 is the closest homolog of tobacco Osmotic Stress-Activated Protein Kinase in Arabidopsis (Arabidopsis thaliana). Comparative analysis of seedling growth of snrk2.4 knockout mutants versus wild-type Arabidopsis suggests that SnRK2.4 is involved in the inhibition of root growth triggered by cadmium; the mutants were more tolerant to the stress. Measurements of the level of three major species of phytochelatins (PCs) in roots of plants exposed to Cd²⁺ showed a similar (PC2, PC4) or lower (PC3) concentration in snrk2.4 mutants in comparison to wild-type plants. These results indicate that the enhanced tolerance of the mutants does not result from a difference in the PCs level. Additionally, we have analyzed ROS accumulation in roots subjected to Cd²⁺ treatment. Our data show significantly lower Cd²⁺-induced ROS accumulation in the mutants’ roots. Concluding, the obtained results indicate that SnRK2s play a role in the regulation of plant tolerance to cadmium, most probably by controlling ROS accumulation triggered by cadmium ions.Cadmium is one of the most toxic soil pollutants. Cadmium ions accumulate in plants and affect, via the food chain, animal and human health. In plants, cadmium is taken up by roots and is transported to aerial organs, leading to chromosomal aberrations, growth reduction, and inhibition of photosynthesis, transpiration, nitrogen metabolism, nutrient and water uptake, eventually causing plant death (for review, see DalCorso et al., 2008). Plants are challenged not only by cadmium ions themselves, but also by Cd²⁺-induced harmful effects including oxidative stress (Schützendübel et al., 2001; Olmos et al., 2003; Cho and Seo, 2005; Sharma and Dietz, 2009). The extent of the detrimental effects on plant growth and metabolism depends on the level of cadmium ions present in the surrounding environment and on the plant’s sensitivity to heavy metal stress.Tolerant plants avoid heavy metal uptake and/or induce the expression of genes encoding products involved, directly or indirectly, in heavy metal binding and removal from potentially sensitive sites, by sequestration or efflux (Clemens, 2006). The best-characterized heavy metal binding ligands in plants are thiol-containing compounds metallothioneins and phytochelatins (PCs), whose production is stimulated by Cd²⁺. PCs bind metal ions and transport them to the vacuole, thus reducing the toxicity of the metal in the cytosol (for review, see Cobbett, 2000; Cobbett and Goldsbrough, 2002). PCs are synthesized from reduced glutathione (GSH). Therefore, production of compounds involved in cadmium detoxification and, at the same time, in cadmium tolerance closely depends on sulfur metabolism. So far, our knowledge on the cellular processes induced by cadmium that lead to changes in sulfur metabolism in plants has been rather limited.Protein kinases and phosphatases are considered major signal transduction elements. However, until now only a few of them have been described to be involved in cadmium stress response or sulfur metabolism. For instance, excessive amounts of cadmium or copper activate mitogen-activated protein kinases (MAPKs) in Medicago sativa (Jonak et al., 2004), rice (Oryza sativa; Yeh et al., 2007), and Arabidopsis (Arabidopsis thaliana; Liu et al., 2010). Studies on rice MAPKs involved in heavy metal stress response indicate that the activity of these kinases depends on the oxidative stress induced by Cd²⁺. Moreover, Yeh et al. (2007) suggested that the activation of MAPKs in rice by cadmium or copper required the activity of calcium-dependent protein kinase (CDPK) and PI3 kinase, since the MAPK pathways involved in cadmium and copper stress response could be inhibited by a CDPK antagonist (W7) or a PI3 kinase inhibitor (wortmannin). However, so far the function of the identified kinases in plant adaptation to heavy metal pollution has not been established. There is some information concerning an involvement of CDPK in sulfur metabolism (Liu et al., 2006). Soybean (Glycine max) Ser acetyltransferase (GmSerat2;1), the enzyme that catalyzes the first reaction in the biosynthesis of Cys from Ser, is phosphorylated by CDPK. The phosphorylation has no effect on GmSerat2;1 activity, but it renders the enzyme insensitive to the feedback inhibition by Cys (Liu et al., 2006). There is growing evidence that SnRK2s (for SNF1-related protein kinase2) play a role in the regulation of sulfur metabolism. Most information showing a connection between SnRK2s and sulfur metabolism comes from experiments on the lower plant Chlamydomonas reinhardtii (Davies et al., 1999; Irihimovitch and Stern, 2006; González-Ballester et al., 2008, 2010). SNRK2.1 is considered a general regulator of S-responsive gene expression in C. reinhardtii (González-Ballester et al., 2008).In higher plants the SnRK2 family members are known to be involved in plant response to drought, salinity, and in abscisic acid (ABA)-dependent plant development (Boudsocq and Laurière, 2005; Fujii et al., 2007, 2011; Fujii and Zhu, 2009; Fujita et al., 2009; Nakashima et al., 2009; Kulik et al., 2011). Ten members of the SnRK2 family have been identified in Arabidopsis and in rice (Boudsocq et al., 2004; Kobayashi et al., 2004). All of them, except SnRK2.9 from Arabidopsis, are rapidly activated by treatment with different osmolytes, such as Suc, mannitol, sorbitol, and NaCl, and some of them also by ABA. Results presented by Kimura et al. (2006) suggest that in Arabidopsis, similarly to C. reinhardtii, some SnRK2s are involved in the regulation of S-responsive gene expression and O-acetyl-l-Ser accumulation under limited sulfur supply, indicating that also higher plants’ SnRK2s could be involved in sulfur metabolism.As it was mentioned before, oxidative stress induced by cadmium ions significantly contributes to the metal toxicity. Reactive oxygen species (ROS) can be produced in many different reactions in various compartments of the cell in response to cadmium (Romero-Puertas et al., 2004; Heyno et al., 2008; Tamás et al., 2009). The best-characterized ROS-generating enzymes that take part in the response to cadmium are the plasma-membrane-bound NADPH oxidases (Olmos et al., 2003; Romero-Puertas et al., 2004; Garnier et al., 2006). There are some indications that plant NADPH oxidases are phosphorylated by SnRK2s (Sirichandra et al., 2009), therefore it is highly plausible that SnRK2s play a role in the regulation of ROS accumulation in plants subjected to cadmium stress. Taking into consideration all facts mentioned above we hypothesized that SnRK2s could be involved in the plant response to stress induced by cadmium ions. To verify this conjecture, we analyzed the activity and potential role of selected SnRK2s, in tobacco (Nicotiana tabacum) cells and Arabidopsis plants, in the response to cadmium ions.     

Threshold for onset of injury in Chinook salmon from exposure to impulsive pile driving sounds

The risk of effects to fishes and other aquatic life from impulsive sound produced by activities such as pile driving and seismic exploration is increasing throughout the world, particularly with the increased exploitation of oceans for energy production. At the same time, there are few data that provide insight into the effects of these sounds on fishes. The goal of this study was to provide quantitative data to define the levels of impulsive sound that could result in the onset of barotrauma to fish. A High Intensity Controlled Impedance Fluid filled wave Tube was developed that enabled laboratory simulation of high-energy impulsive sound that were characteristic of aquatic far-field, plane-wave acoustic conditions. The sounds used were based upon the impulsive sounds generated by an impact hammer striking a steel shell pile. Neutrally buoyant juvenile Chinook salmon (Oncorhynchus tshawytscha) were exposed to impulsive sounds and subsequently evaluated for barotrauma injuries. Observed injuries ranged from mild hematomas at the lowest sound exposure levels to organ hemorrhage at the highest sound exposure levels. Frequency of observed injuries were used to compute a biological response weighted index (RWI) to evaluate the physiological impact of injuries at the different exposure levels. As single strike and cumulative sound exposure levels (SEL(ss), SEL(cum) respectively) increased, RWI values increased. Based on the results, tissue damage associated with adverse physiological costs occurred when the RWI was greater than 2. In terms of sound exposure levels a RWI of 2 was achieved for 1920 strikes by 177 dB re 1 μPa(2)?s SEL(ss) yielding a SEL(cum) of 210 dB re 1 μPa(2)?s, and for 960 strikes by 180 dB re 1 μPa(2)?s SEL(ss) yielding a SEL(cum) of 210 dB re 1 μPa(2)?s. These metrics define thresholds for onset of injury in juvenile Chinook salmon.     

Regulation of the Formyl Peptide Receptor 1 (FPR1) Gene in Primary Human Macrophages

The formyl peptide receptor 1 (FPR1) is mainly expressed by mammalian phagocytic leukocytes and plays a role in chemotaxis, killing of microorganisms through phagocytosis, and the generation of reactive oxygen species. A large number of ligands have been identified triggering FPR1 including formylated and non-formylated peptides of microbial and endogenous origin. While the expression of FPR1 in neutrophils has been investigated intensively, knowledge on the regulation of FPR1 expression in polarized macrophages is lacking. In this study we show that primary human neutrophils, monocytes and resting macrophages do express the receptor on their cell surface. Polarization of macrophages with IFNγ, LPS and with the TLR8 ligand 3M-002 further increases FPR1 mRNA levels but does not consistently increase protein expression or chemotaxis towards the FPR1 ligand fMLF. In contrast, polarization of primary human macrophages with IL-4 and IL-13 leading to the alternative activated macrophages, reduces FPR1 cell surface expression and abolishes chemotaxis towards fMLF. These results show that M2 macrophages will not react to triggering of FPR1, limiting the role for FPR1 to chemotaxis and superoxide production of resting and pro-inflammatory M1 macrophages.     

Dopaminergic Modulation of Effort-Related Choice Behavior as Assessed by a Progressive Ratio Chow Feeding Choice Task: Pharmacological Studies and the Role of Individual Differences

Mesolimbic dopamine (DA) is involved in behavioral activation and effort-related processes. Rats with impaired DA transmission reallocate their instrumental behavior away from food-reinforced tasks with high response requirements, and instead select less effortful food-seeking behaviors. In the present study, the effects of several drug treatments were assessed using a progressive ratio (PROG)/chow feeding concurrent choice task. With this task, rats can lever press on a PROG schedule reinforced by a preferred high-carbohydrate food pellet, or alternatively approach and consume the less-preferred but concurrently available laboratory chow. Rats pass through each ratio level 15 times, after which the ratio requirement is incremented by one additional response. The DA D₂ antagonist haloperidol (0.025–0.1 mg/kg) reduced number of lever presses and highest ratio achieved but did not reduce chow intake. In contrast, the adenosine A_2A antagonist MSX-3 increased lever presses and highest ratio achieved, but decreased chow consumption. The cannabinoid CB1 inverse agonist and putative appetite suppressant AM251 decreased lever presses, highest ratio achieved, and chow intake; this effect was similar to that produced by pre-feeding. Furthermore, DA-related signal transduction activity (pDARPP-32(Thr34) expression) was greater in nucleus accumbens core of high responders (rats with high lever pressing output) compared to low responders. Thus, the effects of DA antagonism differed greatly from those produced by pre-feeding or reduced CB1 transmission, and it appears unlikely that haloperidol reduces PROG responding because of a general reduction in primary food motivation or the unconditioned reinforcing properties of food. Furthermore, accumbens core signal transduction activity is related to individual differences in work output.     

Reproductive factors and serum uric acid levels in females from the general population: the KORA F4 study

Objective

Hyperuricemia is associated with an increased risk of metabolic and cardiovascular diseases. There are pronounced sex differences in the levels of uric acid. It is largely unknown whether or not reproductive parameters which induce hormonal changes are responsible for this. We examined if there are associations between reproductive parameters and uric acid levels in a female population-based sample.

Methods

In this cross-sectional analysis, data of 1530 women aged 32 to 81 years participating in the KORA F4 study, conducted between 2006 and 2008 in Southern Germany were used. Reproductive parameters were obtained by standardized interviews. Uric acid levels were tested by the uricase method. The whole study sample and stratified in pre- and postmenopausal women was analyzed.

Results

Menopausal status and earlier age at menarche were associated with higher serum uric acid levels (age-adjusted: p-values 0.003, <0.001 respectively; after multivariable adjustment, including BMI: p-values 0.002, 0.036). A history of oral contraceptive use showed an association with uric acid levels only after multivariable adjustment (p-value 0.009). Hot flushes showed an association with uric acid levels only after age-adjustment (p-value 0.038), but lost significance after adding other confounders. Other reproductive factors, including parity, current or ever use of hormone replacement therapy, current use of oral contraceptives, hysterectomy, bilateral oophorectomy, or depressive mood related to menopausal transition were not associated with uric acid levels.

Conclusions

Postmenopausal status, earlier age at menarche and a history of oral contraceptive use were independently associated with higher serum uric acid concentrations in women from the general population. Further studies, especially longitudinal population-based studies investigating the relationship of female reproductive parameters with uric acid levels are necessary to confirm our findings.     

LRP2 is an auxiliary SHH receptor required to condition the forebrain ventral midline for inductive signals

Sonic hedgehog (SHH) is a regulator of forebrain development that acts through its receptor, patched 1. However, little is known about cellular mechanisms at neurulation, whereby SHH from the prechordal plate governs specification of the rostral diencephalon ventral midline (RDVM), a major forebrain organizer. We identified LRP2, a member of the LDL receptor gene family, as a component of the SHH signaling machinery in the RDVM. LRP2 acts as an apical SHH-binding protein that sequesters SHH in its target field and controls internalization and cellular trafficking of SHH/patched 1 complexes. Lack of LRP2 in mice and in cephalic explants results in failure to respond to SHH, despite functional expression of patched 1 and smoothened, whereas overexpression of LRP2 variants in cells increases SHH signaling capacity. Our data identify a critical role for LRP2 in SHH signaling and reveal the molecular mechanism underlying forebrain anomalies in mice and patients with Lrp2 defects.     

Molecular evolution, structure, and function of peroxidasins

Peroxidasins represent the subfamily 2 of the peroxidase-cyclooxygenase superfamily and are closely related to chordata peroxidases (subfamily 1) and peroxinectins (subfamily 3). They are multidomain proteins containing a heme peroxidase domain with high homology to human lactoperoxidase that mediates one- and two-electron oxidation reactions. Additional domains of the secreted and glycosylated metalloproteins are type C-like immunoglobulin domains, typical leucine-rich repeats, as well as a von Willebrand factor C module. These are typical motifs of extracellular proteins that mediate protein-protein interactions. We have reconstructed the phylogeny of this new family of oxidoreductases and show the presence of four invertebrate clades as well as one vertebrate clade that includes also two different human representatives. The variability of domain assembly in the various clades was analyzed, as was the occurrence of relevant catalytic residues in the peroxidase domain based on the knowledge of catalysis of the mammalian homologues. Finally, the few reports on expression, localization, enzymatic activity, and physiological roles in the model organisms Drosophila melanogaster, Caenorhabditis elegans, and Homo sapiens are critically reviewed. Roles attributed to peroxidasins include antimicrobial defense, extracellular matrix formation, and consolidation at various developmental stages. Many research questions need to be solved in future, including detailed biochemical/physical studies and elucidation of the three dimensional structure of a model peroxidasin as well as the relation and interplay of the domains and the in vivo functions in various organisms including man.     

Cell analysis in cerebrospinal fluid (CSF) using Sysmex? hematology analyzers XT-4000i and XE-5000: evaluation with CSF controls of the Joint German Society for Clinical Chemistry and Laboratory Medicine (DGKL)

In cerebrospinal fluid (CSF) analysis, hematology analyzers (HAs) Sysmex? XT-4000i and XE-5000, equipped with flow cytometry (FCM), were used to count cells and differentiate leukocytes into mononuclear and polymorphonuclear cells (MNCs, PMCs) applying body fluid mode. FCM was evaluated with 20 DGKL CSF controls containing viable human leukocytes and erythrocytes. HA values were compared with reference values by Passing/Bablok regression analysis to reveal conformity. Conformity of white blood cells (WBCs) was obtained with native leukocytes, counted in calibrated Fuchs-Rosenthal chamber as reference; red blood cell counts proved inaccurate. CV <40% with WBC counts <20 per μL impairs accuracy. Reference WBC differentiation was assayed using FACS Canto II? and FC-500 SN with anti-CD45, anti-CD14, anti-CD16, anti-CD16/56 [Becton Dickinson (BD); Beckman Coulter (BC)]. BD FACS lysing solution?-no-wash-procedure was applied. BC pretreatment with Versalyse lysing solution was not recommended. MNCs (lymphocytes + monocytes) were significantly lower (～14%) on both HAs; PMCs (granulocytes or sum of neutrophils + eosinophils + basophils: range 1-86 M/L) were significantly higher (～2.2-fold). WBC HA differentiation is not reliable because MNC/PMC differentiation yielded lower and higher values than FACS-FCM references, respectively. This is attributed to incorrect discrimination of leukocytes with rounded/nonrounded nuclei; adding leukocytes with nonrounded nuclei to too low HA MNCs (about 40% not-activated) yielded P/B conformity; subtraction of leukocytes with nonrounded nuclei from elevated HA PMCs showed conformity (about 85% activated). Nucleus/activation state of leukocytes was assessed using microhistology. Sysmex XT-4000i and XE-5000 HAs systems are inappropriate for complete CSF cell analysis.