The cumulative electrostatic effect of aromatic stacking interactions and the negative electrostatic environment of the flavin mononucleotide binding site is a major determinant of the reduction potential for the flavodoxin from Desulfovibrio vulgaris [Hildenborough]

Flavodoxins are typified by the very low one-electron reduction potential for the semiquinone/hydroquinone couple (Esq/hq) of the flavin mononucleotide (FMN) cofactor. In the Desulfovibrio vulgaris flavodoxin, the elimination of the side chain of Tyr98, which flanks the outer or si face of the flavin, through the Y98A mutation results in a substantial increase in Esq/hq of 139 mV, representing about one-half of the total shift in Esq/hq in this flavodoxin [Swenson, R. P., & Krey, G. D. (1994) Biochemistry 33, 8505-8514]. The extent to which this large effect was the result of the elimination of unfavorable coplanar aromatic stacking interactions or to the greater solvent exposure of the flavin ring was not known. The significance of the latter effect was heightened by the characterization of the Fld+6 mutant which demonstrated that the unfavorable interaction between the negative electrostatic environment provided by the asymmetric clustering of acidic residues surrounding the cofactor and the FMN hydroquinone anion is responsible for about one-third of the total decrease in Esq/hq in this flavodoxin [Zhou, Z., & Swenson, R. P. (1995) Biochemistry 34, 3183-3192]. In this study, a flavodoxin mutant was generated in which an alanine was substituted for Tyr98 while at the same time the negative electrostatic surface was partially neutralized by the substitution of the six acidic amino acid residues with their amide equivalents. The Esq/hq value of this mutant was found to have increased by 221 mV relative to wild type, which accounts for 70-80% of the total shift in Esq/hq in this flavodoxin. This increase is very similar to the sum of the individual changes in Esq/hq introduced independently in the Y98A and Fld+6 mutants. The similarity in the magnitude of the effect of the neutralization of the six acidic residues in the context of an alanine residue at position 98 (Y98A) relative to an aromatic tyrosine residue (wild type) suggests that the increase in Esq/hq observed for the Y98A mutant is more likely due to the elimination of unfavorable pi-pi interactions between Tyr98 and the FMN hydroquinone rather than to the increased solvent exposure of the flavin. This study provides further support for the concept that the cumulative effect of the unfavorable electrostatic interactions introduced by coplanar aromatic or pi-pi stacking interactions and the negative electrostatic environment of the FMN binding site is a major determinant of the low one-electron reduction potential of the flavodoxin.

Neointimal hyperplasia after arterial injury is increased in a rat model of non-insulin-dependent diabetes mellitus

BACKGROUND

The key biological determinants that promote restenosis in the setting of diabetes have not been elucidated. There is no accepted animal model to study restenosis in diabetes.

METHODS AND RESULTS

We evaluated 2 models of diabetes mellitus: (1) streptozotocin (STZ)-treated Sprague-Dawley rats (type I diabetes) versus regular Sprague-Dawley rats and (2) obese Zucker rats (type II diabetes) versus lean Zucker rats. Neointimal hyperplasia was assessed after carotid balloon injury at 21 days by computerized morphometry. There was no difference in neointimal area in the STZ-treated rats compared with controls, irrespective of insulin administration or dose of STZ. Neointimal area was increased >2-fold in obese Zucker rats compared with lean Zucker rats (0.21+/-0.06 versus 0.08+/-0.03 mm(2), P<0.01). The neointimal area was markedly increased in the obese Zucker rats 7 days after injury (0.058+/-0.024 versus 0.033+/-0.009 mm(2), P<0.05) and persisted through 21 days. In both obese and lean Zucker rats, cell proliferation peaked in the media at 3 days (118.66+/-84.28 versus 27.50+/-12.75 bromodeoxyuridine-labeled cells per cross section). In the intima, cell proliferation markedly increased beginning at day 3 and persisted through day 14 in the obese and lean Zucker rats (202.27+/-98.86 versus 35.71+/-20.54 bromodeoxyuridine-labeled cells at 7 days).

CONCLUSIONS

The type II diabetic rat model, typifying insulin resistance, is associated with a propensity for neointima. The obese Zucker rat model may be an ideal diabetic model to further characterize the diabetic vascular response to injury.

STRIPAK complexes in cell signaling and cancer

Striatin-interacting phosphatase and kinase (STRIPAK) complexes are striatin-centered multicomponent supramolecular structures containing both kinases and phosphatases. STRIPAK complexes are evolutionarily conserved and have critical roles in protein (de)phosphorylation. Recent studies indicate that STRIPAK complexes are emerging mediators and regulators of multiple vital signaling pathways including Hippo, MAPK (mitogen-activated protein kinase), nuclear receptor and cytoskeleton remodeling. Different types of STRIPAK complexes are extensively involved in a variety of fundamental biological processes ranging from cell growth, differentiation, proliferation and apoptosis to metabolism, immune regulation and tumorigenesis. Growing evidence correlates dysregulation of STRIPAK complexes with human diseases including cancer. In this review, we summarize the current understanding of the assembly and functions of STRIPAK complexes, with a special focus on cell signaling and cancer.

Uridine reverses the toxicity of 3'-azido-3'-deoxythymidine in normal human granulocyte-macrophage progenitor cells in vitro without impairment of antiretroviral activity

We evaluated the effects of natural purine and pyrimidine nucleosides on protection from or reversal of 3'-azido-3'-deoxythymidine (AZT) cytotoxicity in human bone marrow progenitor cells by using clonogenic assays. The selectivity of the "protection" or "rescue" agents was examined in evaluating the antiretroviral activity of AZT in combination with these modulating agents and of AZT alone. Following exposure of human granulocyte-macrophage progenitor cells for 2 h to 5 microM AZT (70% inhibitory concentration), increasing concentrations of potential rescue agents were added. Cells were cultured, and colony formation was assessed after 14 days. At concentrations of up to 50 microM no natural 2'-deoxynucleosides, including thymidine, were able to reverse the toxic effects of AZT. Dose-dependent reversal was observed with uridine and cytidine, and essentially complete reversal was achieved with 50 microM uridine. In the protection studies, 100 microM thymidine almost completely antagonized the inhibition of granulocyte-macrophage colony formation produced by 1 microM AZT (50% inhibitory concentration), and 50 microM uridine effected 60% protection against a toxic concentration of AZT (5 microM) (70% inhibitory concentration). The antiretroviral activity of AZT in human peripheral blood mononuclear cells, assessed by revere transcriptase assays, was substantially decreased in the presence of thymidine, whereas no impairment of suppression of viral replication was observed in the presence of uridine in combination with AZT at a molar ratio (uridine/AZT) as high as 10,000. This demonstration of the capacity of uridine to selectively rescue human bone marrow progenitor cells from the cytotoxicity of AZT suggests that use of uridine rescue regimen with AZT may have potential therapeutic benefit in the treatment of acquired immunodeficiency syndrome.

Transgenic approaches to define the functional role of dual site phospholamban phosphorylation

Phospholamban is a critical regulator of the sarcoplasmic reticulum Ca2+-ATPase activity and myocardial contractility. Phosphorylation of phospholamban occurs on both Ser16 and Thr17 during isoproterenol stimulation. To determine the physiological significance of dual site phospholamban phosphorylation, we generated transgenic models expressing either wild-type or the Ser16 --> Ala mutant phospholamban in the cardiac compartment of the phospholamban knockout mice. Transgenic lines with similar levels of mutant or wild-type phospholamban were studied in parallel. Langendorff perfusion indicated that the basal hyperdynamic cardiac function of the knockout mouse was reversed to the same extent by reinsertion of either wild-type or mutant phospholamban. However, isoproterenol stimulation was associated with much lower responses in the contractile parameters of mutant phospholamban compared with wild-type hearts. These attenuated responses were due to lack of phosphorylation of mutant phospholamban, assessed in 32P labeling perfusion experiments. The lack of phospholamban phosphorylation in vivo was not due to conversion of Ser16 to Ala, since the mutated phospholamban form could serve as substrate for the calcium-calmodulin-dependent protein kinase in vitro. These findings indicate that phosphorylation of Ser16 is a prerequisite for Thr17 phosphorylation in phospholamban, and prevention of phosphoserine formation results in attenuation of the beta-agonist stimulatory responses in the mammalian heart.

Determination of allicin, S-allylcysteine and volatile metabolites of garlic in breath, plasma or simulated gastric fluids

Various components of garlic and aged garlic extract, including allicin, S-allylcysteine (SAC) and volatile metabolites of allicin were determined in breath, plasma and simulated gastric fluids by HPLC, gas chromatography (GC) or HPLC- and GC-mass spectrometry (MS). Data indicate that allicin decomposes in stomach acid to release allyl sulfides, disulfides and other volatiles that are postulated to be metabolized by glutathione and/or S-adenosylmethionine to form allyl methyl sulfide. SAC can be absorbed by the body and can be determined in plasma by HPLC or HPLC-MS using atmospheric pressure chemical ionization (APCI)-MS.

High-resolution NMR spectroscopy of lipid A molecules containing 4-amino-4-deoxy-L-arabinose and phosphoethanolamine substituents. Different attachment sites on lipid A molecules from NH4VO3-treated Escherichia coli versus kdsA mutants of Salmonella typhimurium

When Escherichia coli are grown on LB broth containing 25 mm NH(4)VO(3), complex modifications to the lipid A anchor of lipopolysaccharide are induced. Six modified lipid As (EV1-EV6) have been purified. Many of these variants possess 4-amino-4-deoxy-l-arabinose (l-Ara4N) and/or phosphoethanolamine (pEtN) substituents. Here we use NMR spectroscopy to investigate the attachment sites of the l-Ara4N and pEtN moieties on underivatized, intact EV3 and EV6 and on precursors II(A) and III(A) from kdsA mutants of Salmonella. CDCl(3)/CD(3)OD/D(2)O (2:3:1, v/v) is shown to be a superior solvent for homo- and heteronuclear one- and two-dimensional NMR experiments. The latter were not feasible previously because available solvents caused sample decomposition. Selective inverse decoupling difference spectroscopy is used to determine the attachment sites of substituents on EV3, EV6, II(A), and III(A). l-Ara4N is attached via a phosphodiester linkage to the 4'-phosphates of EV3 and EV6 and has the beta anomeric configuration. pEtN is attached by a pyrophosphate linkage to the 1-phosphate of EV6. The l-Ara4N and pEtN substituents of lipids II(A) and III(A) are attached in the opposite manner, with l-Ara4N on the 1-phosphate of II(A) and pEtN on the 4'-phosphate of III(A). Determination of the proper attachment sites of these substituents is necessary for elucidating the enzymology of lipid A biosynthesis and for characterizing polymyxin-resistant mutants, in which l-Ara4N and pEtN substituents are greatly increased.

Long-term use of IgA-depleted intravenous immunoglobulin in immunodeficient subjects with anti-IgA antibodies

The use of intravenous immunoglobulin is standard practice for antibody replacement in the humoral immunodeficiency diseases. Most infusions proceed uneventfully, but a proportion of infusions (5-8%) produces some degree of an infusion reaction. While the cause of most of these infusion reactions is unknown, an established, but rare cause of reactions is IgA antibodies in the serum of the patient, which apparently forms an immune complex with the traces of IgA in the infused immunoglobulin. This article describes our studies of five immunodeficient patients who had high-titered anti-IgA antibodies and a history of severe infusion reactions to intravenous immunoglobulin products not depleted of IgA (IgA content, 270-720 micrograms/ml). Over a 6-year period we gave these patients IgA-depleted intravenous immunoglobulin for a total of 170 infusions. These infusions were generally well tolerated; however, mild to moderate infusion reactions did occur in 9 of the 170 infusions (5.3%). These reactions were not related to the IgA content of the immunoglobulin solutions used--ascertained to vary between 0.4 and 2.9 micrograms/ml of IgA. Levels of plasma C3a and C4a increased after immunoglobulin infusions but the appearance of these components was not accompanied by any infusion reaction. We conclude that the long-term infusions of IgA-depleted intravenous immunoglobulin, within the range of IgA concentrations investigated, into patients with even very high-titered antibodies to IgA, is a safe practice.

Cardiovascular MRI with ferumoxytol

The practice of contrast-enhanced magnetic resonance angiography (CEMRA) has changed significantly in the span of a decade. Concerns regarding gadolinium (Gd)-associated nephrogenic systemic fibrosis in those with severely impaired renal function spurred developments in low-dose CEMRA and non-contrast MRA as well as efforts to seek alternative MR contrast agents. Originally developed for MR imaging use, ferumoxytol (an ultra-small superparamagnetic iron oxide nanoparticle), is currently approved by the US Food and Drug Administration for the treatment of iron deficiency anaemia in adults with renal disease. Since its clinical availability in 2009, there has been rising interest in the scientific and clinical use of ferumoxytol as an MR contrast agent. The unique physicochemical and pharmacokinetic properties of ferumoxytol, including its long intravascular half-life and high r1 relaxivity, support a spectrum of MRI applications beyond the scope of Gd-based contrast agents. Moreover, whereas Gd is not found in biological systems, iron is essential for normal metabolism, and nutritional iron deficiency poses major public health challenges worldwide. Once the carbohydrate shell of ferumoxytol is degraded, the elemental iron at its core is incorporated into the reticuloendothelial system. These considerations position ferumoxytol as a potential game changer in the field of CEMRA and MRI. In this paper, we aim to summarise our experience with the cardiovascular applications of ferumoxytol and provide a brief synopsis of ongoing investigations on ferumoxytol-enhanced MR applications.

Effects of fluid flow on intracellular calcium in bovine articular chondrocytes

Fluid flow-induced shear stress results in a variety of morphological and metabolic changes in cultured bovine articular chondrocytes (BAC). However, the mechanism by which the flow signal is transduced into a biological response is unknown. Therefore, we investigated the effects of fluid flow on intracellular Ca2+ concentration ([Ca2+]i) in BAC. Cells loaded with fura 2 were exposed to steady and pulsatile (0.5 Hz) flow at 9, 18, and 34 ml/min in a parallel-plate flow chamber. In response to flow, there was a significant and flow rate-dependent increase in the percentage of cells showing a rise in [Ca2+]i, but no effect on the [Ca2+]i response amplitude. There was no significant difference between the [Ca2+]i responses to steady and pulsatile flow. Mean intracellular Ca2+ response values ranged between 26.2 +/- 1.6 (9 ml/min) and 38.0 +/- 6.8 nM (34 ml/min) above basal [Ca2+]i (81.3 +/- 24.1 nM, n = 90). Removal of extracellular Ca2+ or addition of Gd3+ significantly reduced the percentage of cells responding, suggesting that influx of Ca2+, possibly through mechanosensitive channels, contributes to the rise in intracellular Ca2+. Our data suggest fluid flow-induced mobilization of intracellular Ca2+ may contribute to the mechanism by which mechanical loads are transduced by chondrocytes.

Identification of a splice site mutation (2789 +5 G > A) associated with small amounts of normal CFTR mRNA and mild cystic fibrosis

A splicing mutation was identified at the +5 position of the splice donor site of exon 14b of CFTR in CF patients in a consanguineous family that is remarkable for unusually mild disease. Quantitative studies of nasal epithelial mRNA revealed that homozygotes for the spice site mutation produced approximately 4% of the normal amount of normally-spliced CFTR. We propose that this small amount of normally spliced mRNA is associated with synthesis of some normal CFTR protein, and accounts for the mild phenotype. Further characterization of epithelial function and clinical phenotype in patients bearing this form of mutation, termed a type V mutation, will be useful in determining the level of CFTR associated with amelioration of lung disease.

Fluid flow-induced prostaglandin E2 response of osteoblastic ROS 17/2.8 cells is gap junction-mediated and independent of cytosolic calcium

It has been well demonstrated that bone adapts to mechanical loading. To accomplish this at the cellular level, bone cells must be responsive to mechanical loading (mechanoresponsive). This can occur via such mechanisms as direct cell deformation or signal transduction via complex pathways involving chemotransport, hormone response, and/or gene expression, to name a few. Mechanotransduction is the process by which a bone cell senses a biophysical signal and elicits a response. While it has been demonstrated that bone cells can respond to a wide variety of biophysical signals including fluid flow, stretch, and magnetic fields, the exact pathways and mechanisms involved are not clearly understood. We postulated that gap junctions may play an important role in bone cell responsiveness. Gap junctions (GJ) are membrane-spanning channels that physically link cells and support the transport of small molecules and ions in the process of gap junctional intercellular communication (GJIC). In this study we examined the role of GJ and GJIC in mechanically stimulated osteoblastic cells. Following fluid flow stimulation, we quantified prostaglandin E(2) (PGE(2)) (oscillatory flow) and cytosolic calcium (Ca(2+)) (oscillatory and steady flow) responses in ROS 17/2.8 cells and a derivative of these cells expressing antisense cDNA for the gap junction protein connexin 43 (RCx16) possessing significantly different levels of GJIC. We found that the ROS17/2.8 cells possessing increased GJIC also exhibited increased PGE(2) release to the supernatant following oscillatory fluid flow stimulation in comparison to coupling-decreased RCx16 cells. Interestingly, we found that neither osteoblastic cell line responded to oscillatory or steady fluid flow stimulation with an increase in Ca(2+). Thus, our results suggest that GJ and GJIC may be important in the mechanotransduction mechanisms by which PGE(2) is mechanically induced in osteoblastic cells independent of Ca(2+).

Early Adaptive Radiation of Birds: Evidence from Fossils from Northeastern China

Late Jurassic and Early Cretaceous birds from northeastern China, including many complete skeletons of Confuciusornis, provide evidence for a fundamental dichotomy in the class Aves that may antedate the temporal occurrence of the Late Jurassic Archaeopteryx. The abundance of Confuciusornis may provide evidence of avian social behavior. Jurassic skeletal remains of an ornithurine bird lend further support to the idea of an early separation of the line that gave rise to modern birds. Chaoyangia, an ornithurine bird from the Early Cretaceous of China, has premaxillary teeth.

Identification of immune system and response genes, and novel mutations causing melanotic tumor formation in Drosophila melanogaster

We are using Drosophila as a model system for analysis of immunity and tumor formation and have conducted two types of screens using enhancer detector strains to find genes related to these processes; genes expressed in the immune system (type A; hemocytes, lymph glands and fat body) and genes increased in expression by bacterial infection (type B). For type A, tissue-specific reporter gene activity was determined. For type B, a variation of enhancer detection was devised in which beta-galactosidase is assayed spectrophotometrically with and without bacterial infection. Because of immune system involvement in melanotic tumor formation, a third type was hypothesized to be found among types A and B; genes that, when mutated, have a melanotic tumor phenotype. Enhancer detector strains (2800) were screened for type A, 900 for B, and 11 retained for further analysis. Complementation tests, cytological mapping, P-element mobilization, and determination of lethal phase and mutant phenotype have identified six novel genes, Dorothy, wizard, toto, viking, Thor and dappled, and one previously identified gene, Collagen IV. All are associated with reporter gene expression in at least one immune system tissue. Thor has increased expression upon infection. Mutations of wizard and dappled have a melanotic tumor phenotype.

Cellular and subcellular localization of catalase in the heart of transgenic mice

Previous studies have described a cardiac-specific, catalase-overexpressing transgenic mouse model that was used to study myocardial oxidative injury. This study was undertaken to demonstrate cellular and subcellular localization of catalase in the hearts of transgenic mice. By the light microscopic immunoperoxidase method, we found that the overexpressed catalase was exclusively localized in cardiomyocytes. The ratios of immunoreactive cardiomyocytes in the heart were quite different among three transgenic lines examined but agreed with the elevated levels of catalase activity. In the cardiac blood vessels, positive cells were found in the walls of pulmonary veins and the vena cava, which consist of cardiomyocytes, but not in the pulmonary arteries, aorta, or cardiac valves. The electron microscopic immunogold method revealed that the elevated catalase was in sarcoplasm, nucleus, and peroxisomes, but not in mitochondria. In contrast to these distributions, catalase in the non-transgenic cardiomyocytes was in peroxisomes only. In addition, the number and size of peroxisomes in the transgenic cardiomyocytes were markedly increased, but no other ultrastructural changes were observed in comparison with those of non-transgenic mice. These results demonstrated that the elevated catalase in transgenic mouse heart is localized in cardiomyocytes and is distributed to peroxisomal and extraperoxisomal, but not mitochondrial, compartments.

Land use affects the relationship between species diversity and productivity at the local scale in a semi-arid steppe ecosystem

1

The accelerating extinction rate of plant species and its effect on ecosystem functioning is a hotly debated topic in ecological research. Most research projects concerning the relationship between species diversity and productivity have been conducted in artificial plant communities, with only a few in natural ecosystems. In this study we examined the relationship between species diversity and above‐ground net primary productivity (ANPP) over two consecutive growth seasons (2004 and 2005) in a semi‐arid steppe ecosystem of northern China, that were subjected to different land uses.

2

Land use affected the relationship between species diversity and ANPP in this semi‐arid steppe ecosystem. Exclusion of grazing without or with biomass removal by mowing increased ANPP, species richness and species diversity compared with free grazing; the effect was reflected mainly as enhanced importance of the perennial forbs functional group in terms of their relative contributions to ANPP, plant cover and plant abundance.

3

Many mechanisms regulate the relationship between species diversity and productivity. Differential effects of anthropogenic activities on biodiversity and ecosystem functioning greatly complicate the analysis of such relationships. On grazing‐exclusion sites the relationship between ANPP and species richness can be best described as an exponential growth function (R² = 0·99, P < 0·001, n = 24); whereas on the free‐grazing site the relationship takes the form of exponential decay (R² = 0·96, P < 0·001, n = 24). Our study concludes that the mode and severity of disturbance are important factors for interpreting the relationship between species diversity and productivity in semi‐arid steppe ecosystems.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and [Formula: see text] credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5-[Formula: see text] requires at least three detectors of sensitivity within a factor of [Formula: see text] of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

Regulation of the expression of soluble guanylyl cyclase by reactive oxygen species

BACKGROUND AND PURPOSE

Superoxide anions produced during vascular disease scavenge nitric oxide (NO), thereby reducing its biological activity. The aim of the present study was to investigate whether reactive oxygen species (ROS) have a direct effect on soluble guanylyl cyclase (sGC) subunit levels and function and to ascertain the mechanism(s) involved.

EXPERIMENTAL APPROACH

Rat aortic smooth muscle cells (RASM) or freshly isolated vessels were exposed to reactive oxygen species (ROS)-generating agents and sGC subunit expression was determined at the mRNA and/or protein level. cGMP accumulation was also determined in RASM exposed to ROS.

KEY RESULTS

Incubation of smooth muscle cells with H(2)O(2), xanthine/xanthine oxidase (X/XO) or menadione sodium bisulphite (MSB) significantly decreased protein levels of alpha1 and beta1 subunits of sGC and reduced SNP-induced cGMP formation. Similarly, sGC expression was reduced in freshly isolated vessels exposed to ROS-generating agents. The ROS-triggered inhibition of alpha1 and beta1 levels was not blocked by proteasome inhibitors, suggesting that decreased sGC protein was not due to protein degradation through this pathway. Real time RT-PCR analysis demonstrated a 68% reduction in steady state mRNA levels for the alpha1 subunit following exposure to H(2)O(2). In addition, alpha1 promoter-driven luciferase activity in RASM decreased by 60% after H(2)O(2) treatment.

CONCLUSION AND IMPLICATIONS

We conclude that oxidative stress triggers a decrease in sGC expression and activity that results from reduced sGC steady state mRNA levels. Altered sGC expression is expected to contribute to the changes in vascular tone and remodeling observed in diseases associated with ROS overproduction.

Antibody against murine PECAM-1 inhibits tumor angiogenesis in mice

Platelet endothelial cell adhesion molecule (PECAM-1/CD31), a member of the immunoglobulin superfamily expressed at high levels on endothelial cells, has been recently implicated in angiogenesis. Although antagonism of PECAM-1 inhibited neovascularization in two different animal models of growth factor/chemokine-induced angiogenesis, its participation in tumor angiogenesis has not been established. We therefore investigated its involvement in models of tumor angiogenesis in mice. An antibody against murine PECAM-1 that was shown to block in vitro murine endothelial tube formation inhibited the subcutaneous growth and tumor vascularity of three tumors in mice: A549 human non-small cell lung cancer in SCID mice, B16 murine melanoma in C57BL/6 mice and AB12 murine mesothelioma in Balb/c mice. These studies suggest a possible role for PECAM-1 in the complex process of tumor angiogenesis and provide additional evidence of the importance of endothelial cell adhesion molecules to the formation of new vessels.

Pregnancy and lactation are associated with diminished concentrations of choline and its metabolites in rat liver

Choline is an important nutrient that is actively transported from mother to fetus across the placenta and from mother to infant across the mammary gland. Thus, pregnancy and lactation are times when dietary requirements for choline may be increased. Pregnant rats eating AIN-76A diet (with and without choline) for 6 d (d 12-18 gestation) were compared with nonmated female and male rats eating the same diets. Similarly, lactating rats were compared with nonmated female rats, both groups eating these same diets for 25 d (gestation d 12-postpartum d 15). We measured choline and choline metabolites in livers on the last day of feeding. Nonmated female rats, eating the control diet, had higher hepatic choline metabolites concentrations than did male rats (choline, 98%; betaine, 96%; and phosphorylcholine, 55% higher), pregnant rats (phosphorylcholine, 47%; and betaine, 42% higher) or lactating rats (phosphorylcholine, 49%; phosphatidylcholine, 37%; and betaine, 273% higher). We found that nonmated females eating a choline deficient diet had only a modest diminution (33%) of the labile choline metabolite PCho in liver, compared with similar rats eating a control diet. When compared with similar rats fed a choline-adequate diet, pregnant rats fed a choline-deficient diet had significantly great diminution of hepatic phosphorylcholine (83% lower) than did nonmated females. Liver phosphorylcholine was only 12% lower than in controls in nonmated females fed the deficient diet for the same 25-d period. Lactating rats were the most sensitive to choline deficiency, with liver phosphorylcholine 88% lower than in similar rats fed control diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Pheromone-induced signal transduction in Saccharomyces cerevisiae requires the sequential function of three protein kinases

Protein phosphorylation plays an important role in pheromone-induced differentiation processes of haploid yeast cells. Among the components necessary for signal transduction are the STE7 and STE11 kinases and either one of the redundant FUS3 and KSS1 kinases. FUS3 and presumably KSS1 are phosphorylated and activated during pheromone induction by a STE7-dependent mechanism. Pheromone also induces the accumulation of STE7 in a hyperphosphorylated form. This modification of STE7 requires the STE11 kinase, which is proposed to act before STE7 during signal transmission. Surprisingly, STE7 hyperphosphorylation also requires a functional FUS3 (or KSS1) kinase. Using in vitro assays for FUS3 phosphorylation, we show that pheromone activates STE7 even in the absence of FUS3 and KSS1. Therefore, STE7 activation must precede modification of FUS3 (and KSS1). These findings suggest that STE7 hyperphosphorylation is a consequence of its activation but not the determining event.

Cocaine blocks HERG, but not KvLQT1+minK, potassium channels

Cocaine causes cardiac arrhythmias, sudden death, and occasionally long QT syndrome in humans. We investigated the effect of cocaine on the human K(+) channels HERG and KvLQT1+minK that encode native rapidly (I(Kr)) and slowly (I(Ks)) activating delayed rectifier K(+) channels in the heart. HERG and KvLQT1+minK channels were heterologously expressed in human embryonic kidney 293 cells, and whole-cell currents were recorded. Cocaine had no effect on KvLQT1+minK current in concentrations up to 200 microM. In contrast, cocaine reversibly blocked HERG current with half-maximal block of peak tail current of 7.2 microM. By using a protocol to quickly activate HERG channels, we found that cocaine block developed rapidly after channel activation. At 0 mV, the time constants for the development of block were 38.2 +/- 2.1, 15.2 +/- 0.8, and 6.9 +/- 1.1 ms in 10, 50 and 200 microM cocaine, respectively. Cocaine-blocked channels also recovered rapidly from block after repolarization. At -100 mV, recovery from block followed a biphasic time course with fast and slow time constants of 3.5 +/- 0.7 and 100.3 +/- 15.4 ms, respectively. Using N-methyl-cocaine, a permanently charged, membrane-impermeable cocaine analog, block of HERG channels rapidly developed when the drug was applied intracellularly through the patch pipette, suggesting that the cocaine binding site on the HERG protein is located on a cytoplasmic accessible domain. These results indicate that cocaine suppresses HERG, but not KvLQT1+minK, channels by preferentially blocking activated channels, that it unblocks upon repolarization, and does so with unique ultrarapid kinetics. Because the cocaine concentration range we studied is achieved in humans, HERG block may provide an additional mechanism for cocaine-induced arrhythmias and sudden death.

Prospects for Observing and Localizing Gravitational-Wave Transients with Advanced LIGO and Advanced Virgo

We present a possible observing scenario for the Advanced LIGO and Advanced Virgo gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We determine the expected sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron-star systems, which are considered the most promising for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and 90% credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5 deg2 to 20 deg2 will require at least three detectors of sensitivity within a factor of ∼ 2 of each other and with a broad frequency bandwidth. Should the third LIGO detector be relocated to India as expected, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

Rapid disease progression correlates with instability of mutant SOD1 in familial ALS

Studies on the clinical course of familial ALS suggest that the duration of illness is relatively consistent for each mutation but variable among the different mutations. The authors analyzed the relative amount of mutant compared with normal SOD1 protein in the erythrocytes from 29 patients with ALS with 22 different mutations. Turnover of mutant SOD1 correlated with a shorter disease survival time.