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Phytochrome A (phyA) comprises two native types, phyA′ and phyA″, with distinct spectroscopic, photochemical, and functional properties, differing at the N-terminal extension, probably, by the state of phosphorylation. To find out if and how protein phosphatases (PP) affect the state of the phyA species in planta, we studied the effect of the non-specific phosphatase inhibitor NaF on etiolated maize seedlings with the use of low-temperature fluorescence spectroscopy and photochemistry. In roots, phosphatase inhibition facilitated photoreceptor destruction in its labile phyA′ form and shifted the phyA′/phyA″ ratio towards the more stable phyA″. The effect of NaF was not observed in stems. It was similar, though less pronounced, in comparison to the effects of the serine/threonine PP inhibitors, okadaic and cantharidic acids (OA and CA), which likewise facilitate the destruction of phyA′ in etiolated maize stems, not, however, in roots (Sineshchekov et al., Photochem. Photobiol 89:83–96, 2013). The phyA′/phyA″ balance thus depends on the kinase/phosphatase equilibrium in the root cells. The relatively low effect of NaF on phyA in roots, together with the lack of the effect of OA and CA in them, may imply that the mechanism controlling the phyA′/phyA″ balance in roots can be different from that in shoots.

Interaction between phytochromes and hormones is becoming one of the major issues in plant photophysiology. In this work, effects of defense-related jasmonic acid (JA) on phytochrome A (phyA) were investigated by fluorescence spectroscopy making use of two JA biosynthesis mutants of rice: cpm2 with the inactivated gene allene oxide cyclase and hebiba with additional genes deleted. Constant far-red light (FRc) mediated by phyA reduced its content in the wild type (WT) and mutants, and brought about domination of its light-stable pool (phyA″) in WT and light-labile pool (phyA') in the mutants. Pulsed FRp was much less effective. This FR effect classifies as primarily HIR with a low fluence threshold; it comprises inhibition of phyA biosynthesis, stimulation of phyA″→phyA' transformation and phyA' destruction. In the mutants, phyA suppresses [Pchlide] under FRp (VLFR) and stimulates it under FRc (HIR); these effects are lacking in WT. Similarly, phyA suppresses roots'growth under FRp in the mutants but not in WT. These JA mutant features suggest that JA reduces the phyA functional activity primarily in its phyA″ form mediating HIR. This modulating JA action on phyA functions under FR limiting their extreme manifestations may have contributed to the evolutionary advances of the land plants.

Phytochrome A (phyA) is represented in plants by two species, phyA' and phyA'', with different properties and modes of action (Sineshchekov, Funct. Plant Biol., 2019, 46, 118-135). They differ by the modification of a serine(s) residue at the N-terminus, possibly, by phosphorylation. To verify if these serines could be the Ser8 and Ser18 (in Avena sativa phyA, AsphyA), whose autophosphorylation modulates AsphyA stability and sensitivity as shown with the use of the serine-to-alanine substitution AsphyA mutants (S8A, S18A and S8/18A) (Han et al., Plant Cell Physiol., 2010, 51, 596-609), we have undertaken low-temperature (85 K) fluorescence investigations of phyA in these transgenic lines. The content and proportion of phyA' and phyA'' were essentially the same in wild-type AsphyA and its mutants, and in endogenous Arabidopsis phyA. All the lines revealed a higher phyA'/phyA'' proportion upon longer germination-inducing preillumination (3 h vs. 15 min white light) supporting our earlier finding that the phyA differentiation into the subpools is light-regulated. These observations and our earlier data imply that this process involves N-terminal serine(s) different from the autophosphorylated Ser8 and Ser18 (in AsphyA) narrowing down the area of further search for the exact site(s) of the phyA modification.

Phytochrome (phy) in etiolated seedlings of wild-type (WT) Arabidopsis (Ler) and its transgenic lines (TL) L15 and L20 transformed with Adiantum capillus-veneris PHY1 cDNA (Okamoto et al., 1997) was investigated using low-temperature (85 K) fluorescence spectroscopy and photochemistry. It was found that while WT seed germination requires stimulation by light, the TL germinated equally well with or without pre-illumination. Phytochrome content [Ptot] was 2-fold higher in TL whereas the level of Pr → lumi-R phototransformation at 85 K (γ1) was similar between WT (0.25) and TL (0.27). When seeds germinated with pre-illumination, the proportion of the photochemical types Pr′ active and Pr″ inactive at 85 K was 50/50 in WT and 54/46 in TL, respectively. Dark-germinated TL had a γ1 value of 0.16 and the proportion of Pr′ and Pr″ was 32/68, respectively, without changes in [Ptot]. Evaluations based on these data revealed that phy1 has Pr′ and Pr″, designated phy1′ and phy1″, akin to phyA, which comprises both Pr photochemical types (phyA′ and phyA″), and in contrast to phyB that possesses only Pr″. The proportion of phy1′ and phy1″ depends on pre-illumination for induction of germination. The pigment most likely accumulated in the seeds and was active in promoting Arabidopsis seed germination.

Good self-control has been linked to adaptive outcomes such as better health, cohesive personal relationships, success in the workplace and at school, and less susceptibility to crime and addictions. In contrast, self-control failure is linked to maladaptive outcomes. Understanding the mechanisms by which self-control predicts behavior may assist in promoting better regulation and outcomes. A popular approach to understanding self-control is the strength or resource depletion model. Self-control is conceptualized as a limited resource that becomes depleted after a period of exertion resulting in self-control failure. The model has typically been tested using a sequential-task experimental paradigm, in which people completing an initial self-control task have reduced self-control capacity and poorer performance on a subsequent task, a state known as ego depletion. Although a meta-analysis of ego-depletion experiments found a medium-sized effect, subsequent meta-analyses have questioned the size and existence of the effect and identified instances of possible bias. The analyses served as a catalyst for the current Registered Replication Report of the ego-depletion effect. Multiple laboratories (k = 23, total N = 2,141) conducted replications of a standardized ego-depletion protocol based on a sequential-task paradigm by Sripada et al. Meta-analysis of the studies revealed that the size of the ego-depletion effect was small with 95% confidence intervals (CIs) that encompassed zero (d = 0.04, 95% CI [−0.07, 0.15]. We discuss implications of the findings for the ego-depletion effect and the resource depletion model of self-control. Contributing authors affiliated with Linköping University are also listed as Contributors in the list of the article's main authors.Contributing authors: Hugo Alberts, Calvin Octavianus Anggono, Cédric Batailler, Angela R. Birt, Ralf Brand, Mark J. Brandt, Gene Brewer, Sabrina Bruyneel, Dustin P. Calvillo, W. Keith Campbell, Peter R. Cannon, Marianna Carlucci, Nicholas P. Carruth, Tracy Cheung, Adrienne Crowell, Denise T. D. De Ridder, Siegfried Dewitte, Malte Elson, Jacqueline R. Evans, Benjamin A. Fay, Bob M. Fennis, Anna Finley, Zoë Francis, Elke Heise, Henrik Hoemann, Michael Inzlicht, Sander L. Koole, Lina Koppel, Floor Kroese, Florian Lange, Kevin Lau, Bridget P. Lynch, Carolien Martijn, Harald Merckelbach, Nicole V. Mills, Alexej Michirev, Akira Miyake, Alexandra E. Mosser, Megan Muise, Dominique Muller, Milena Muzi, Dario Nalis, Ratri Nurwanti, Henry Otgaar, Michael C. Philipp, Pierpaolo Primoceri, Katrin Rentzsch, Lara Ringos, Caroline Schlinkert, Brandon J. Schmeichel, Sarah F. Schoch, Michel Schrama, Astrid Schütz, Angelos Stamos, Gustav Tinghög, Johannes Ullrich, Michelle vanDellen, Supra Wimbarti, Wanja Wolff, Cleoputri Yusainy, Oulmann Zerhouni, Maria Zwienenberg

The green stink bug, Acrosternum hilare (Say) \[ Chinavia hilaris (Say)\] (Hemiptera: Pentatomidae) is one of the most damaging native stink bug species in the United States. It is a pest of economic importance in a variety of commodities, including cotton ( Gossypium hirsutum L.), soybeans [ Glycine max (L.) Merr.], tomatoes ( Solanum lycopersicum L.), and peaches [ Prunus persica (L.) Batsch].Stink bug feeding can result in cosmetic damage as well as reduced quality and yield. Acrosternum hilare and other stink bugs have become a major challenge to integrated pest management systems because control options are basically limited to the application of broad-spectrum insecticides such as organophosphates, carbamates, and pyrethroids. However, neonicotinoids are generally effective for control of this stink bug and may be less disruptive to natural enemies. Further options for stink bug management that are being explored include the use of trap crops and enhancing beneficial parasitoid populations. The green stink bug is native and found throughout the United States. It has a wide host range, and is a pest of many agricultural commodities. The green stink bug can cause feeding injury to fruit, vegetable, and field crops that may require preventative management. Many strategies are available for its control, which include multiple chemical, cultural, and biological options. Broad-spectrum insecticides such as pyrethroids and organophosphates, as well as the less toxic neonicotinoids, are efficacious against the green stink bug. Cultural options, including trap cropping and the planting of resistant varieties, have been documented as decreasing crop injury by stink bugs. In addition, there are multiple natural enemies that reduce population numbers.

Phytochrome A (phyA) mediates different photoresponses what may be connected with the existence of its two types, phyAʹ and phyAʹʹ, differing by spectroscopic, photochemical and functional properties. We investigated a role of phyA phosphorylation in their formation turning to transgenic Arabidopsis thaliana (L. Heynh.) phyA or phyAphyB mutants overexpressing rice wild-type phyA (phyA WT) or mutant phyA (phyA SA) with the first 10 serines substituted by alanines. This prevents phyA phosphorylation at these sites and modifies photoresponses. Etiolated seedlings were employed and phyA parameters were evaluated with the use of low temperature fluorescence spectroscopy and photochemistry. Germination of seeds was induced by white light (WL) pre-treatment for 15 min or 3 h. Emission spectra of rice phyA WT and phyA SA were similar and their total content was comparable. However, the phyAʹ/phyAʹʹ proportion in phyA WT was high and varied with the duration of the WL pre-treatment, whereas in phyA SA it was substantially shifted towards phyAʹʹ and did not depend on the pre-illumination. This suggests that phyA SA comprises primarily or exclusively the phyAʹʹ pool and supports the notion that the two phyA types differ by the state of serine phosphorylation. phyAʹʹ was also found to be much more effective in the germination induction than phyAʹ.

Recombinant dimeric full-length Cph1 holophytochrome and its C-terminally-truncated monomeric species [Cph1Delta2, comprising the chromophore-bearing N-terminal sensory module (residues 1 to 514)] from the cyanobacterium Synechocystis expressed in E. coli and reconstituted in vitro with phycocyanobilin (PCB) were investigated with the use of fluorescence spectroscopy and photochemistry in the temperature range from 85 to 293 K. Holoprotein assembly in Cph1 apparently proceeds via intermediate states with the emission maximum at 680-690 nm (I685) and 700 nm (I700) and a half-life time, at room temperature, of < or =5 s. Conversion of the putative I685 into mature Cph1 involves relaxation of the chromophore into a more flexible conformation. Cph1 and Cph1Delta2 were closely similar in their spectroscopic and photochemical characteristics (position of the emission band and its width, character of the temperature dependence of the fluorescence and activation energy of the fluorescence decay, kinetics and extent of the Pr conversion at low and ambient temperatures), suggesting that there is no immediate effect of the C-terminus on the photochemical properties of the chromophore in Cph1 and that chromophore-chromophore interactions in the dimer are not significant. The latter is also supported by the lack of energy transfer from the phycoerythrobilin (PEB) to PCB in the mixed PEB/PCB adduct of Cph1. At the same time, certain variations in the fluorescence and photochemical parameters of Cph1 with temperature of the sample and intensity of the excitation light and dependence of the emission spectra on excitation wavelength were observed. These variations are interpreted as a manifestation of the Cph1 heterogeneity which may be due to the existence of different conformers of the chromophore and photoproduct formation under excitation light.

The recombinant phytochrome of the moss Ceratodon purpureus (CP2) expressed in Saccharomyces cerevisiae and reconstituted with phycocyanobilin (PCB) was investigated using fluorescence spectroscopy. The pigment had an emission maximum at 670 nm at low temperature (85 K) and at 667 nm at room temperature (RT) and an excitation maximum at 650-652 nm at 85 K (excitation spectra could not be measured at RT). Both spectra had a half-band width of approx. 30-35 nm at 85 K. The fluorescence intensity revealed a steep temperature dependence with an activation energy of fluorescence decay (Ea) of 5.9-6.4 and 12.6-14.7 kJ mol(-1) in the interval from 85 to 210 K and from 210 to 275 K, respectively. The photochemical properties of CP2/PCB were characterised by the extent of the red-induced (lambda(a) = 639 nm) Pr conversion into the first photoproduct lumi-R at 85 K (gamma1) of approximately 0.07 and into Pfr at RT (gamma2) of approximately 0.7. From these characteristics, CP2/PCB can be attributed to the Pr" photochemical type with gamma1or = 0.05, which comprises the minor phyA fraction (phyA"), phyB, Adiantum phy1 and Synechocystis Cph1 in contrast to the major phyA' fraction (Pr' type with gamma1 = 0.5). Within the Pr" type, it is closer to phyA" than to phyB and Cph1.

Hourly surface pressure observations for a 25-yr period (1949–63; 1984–93) for the conterminous United States have been used to map the distribution of large hourly pressure changes defined as falls or rises in excess of 4.25 hPa. Initially, 8431 reports satisfying this pressure change threshold were obtained. After error checking, this number was reduced to 5380 occurrences. Large hourly surface pressure changes are most common over the Great Plains and New England and least common over the Southeast and Southwest. Large pressure falls are confined almost exclusively to the Plains, upper Midwest, and New England, and are virtually absent over the Intermountain West and parts of the Appalachians. A manual (subjective) analysis identified 1038 inertia–gravity wave (IGW) occurrences from the 5380 large hourly surface pressure change occurrences. IGW occurrences are most common across the Plains and from the Great Lakes toward western New England, and are virtually absent across the Intermountain We...

Phytochrome A (phyA), the most versatile plant phytochrome, exists in the two isoforms, phyA′ and phyA′′, differing by the character of its posttranslational modification, possibly, by phosphorylation at the N-terminal extension [Sineshchekov, V. (2010) J. Botany 2010, Article ID 358372]. This heterogeneity may explain the diverse modes of phyA action. We investigated possible roles of protein phosphatases activity and pH in regulation of the phyA pools' content in etiolated seedlings of maize and their extracts using fluorescence spectroscopy and photochemistry of the pigment. The phyA′/phyA′′ ratio varied depending on the state of development of seedlings and the plant tissue/organ used. This ratio qualitatively correlated with the pH in maize root tips. In extracts, it reached a maximum at pH ≈ 7.5 characteristic for the cell cytoplasm. Inhibition of phosphatases of the PP1 and PP2A types with okadaic and cantharidic acids brought about phyA′ decline and/or concomitant increase of phyA′′ in coleoptiles and mesocotyls, but had no effect in roots, revealing a tissue/organ specificity. Thus, pH and phosphorylation status regulate the phyA′/phyA′′ equilibrium and content in the etiolated (maize) cells and this regulation is connected with alteration of the processes of phyA′ destruction and/or its transformation into the more stable phyA′′.

Brown stink bug, Euschistus servus (Say), and green stink bug, Acrosternum hilare (Say) (Hemiptera: Pentatomidae), are major agricultural pests. Although various insecticides are used to control nymphs and adults, little is known about how they affect eggs. Laboratory bioassays and field trials were conducted to determine the efficacy of common field rates of acephate, lamda-cyhalothrin, spinosad, and thiamethoxam on developing E. servus and A. hilare eggs, as well as Telenomus podisi Ashmead (Hymenoptera: Scelionidae) parasitoids developing in E. servus eggs. In laboratory bioassays, egg masses were dipped into insecticide and water solutions and assessed for mortality after 2 wk. In the field trials, egg masses on a cloth section were pinned to leaves in each plot ofa randomized complete block and returned to the laboratory 24 h after exposure to insecticide sprays. Mortality was assessed after 2 wk. In dip bioassays, there was a significant effect of insecticide treatment on A. hilare eggs with all insecticides resulting in greater mortality than the water control. However, no effect of treatment occurred in the field with A. hilare or for E. serous eggs in both the laboratory bioassays and the field trials. In contrast, developing T. podisi parasitoids showed significant mortality when exposed to all insecticide treatments, when dipped or field-treated. Spinosad and lamda-cyhalothrin treatments resulted in 100% mortality of T. podisi, and acephate resulted in greater mortality than thiamethoxam. Our results suggest that there is relatively little efficacy from insecticide sprays on stink bugs developing in eggs but that mortality of egg parasitoids may be significant.

Previous efficacy studies found that many insecticides used by growers could be having an adverse effect on egg parasitoids (Telenomus podisi) developing in the eggs of the brown stink bug (Euschistus servus), while unhatched stink bugs experienced lower levels of mortality. One plausible explanation for this was that insecticides might enter parasitized eggs more readily via oviposition wounds. Parasitized E. servus eggs, as well as nonparasitized stink bug (Acrosternum hilare, E. servus, Murgantia histrionica, and Podisus maculiventris) eggs, were examined using electron microscopy. Egg response to perforation by a tungsten probe served as a control. Microscopy images depicted the chorion surface as characterized by a matrix of ridges and micropylar processes in a ring around the margin of the operculum. Observations of oviposition sites showed a “scab” formed where the ovipositor penetrated the chorion, and at sites penetrated by the probe. These formations appeared to be the result of fluids from inside the egg leaking out, drying, and hardening after oviposition or probe perforation, suggesting that the response was not due to substances secreted by the parasitoid. Further, no open wounds or holes were seen to increase the possibility of insecticides entering parasitized eggs.

Stink bugs (Hemiptera: Pentatomidae) cause significant damage to many different crops and horticultural commodities in Virginia. However, little is known about the species diversity or impact of stink bug egg parasitoids in the state. A survey was conducted in 2005 and 2006 (May through September) in wheat (Triticum aestivum L.), soybean (Glycine max L.), and several vegetable crops by collecting natural egg masses of various stink bug species and by monitoring sentinel egg masses. A total of 570 Euschistus servus (Say) eggs in 26 egg masses, 11,197 Murgantia histrionica (Hahn) eggs in 939 egg masses, 15 Podisus maculiventris (Say) eggs in 2 egg masses, and 546 Acrosternum hilare (Say) eggs in 18 egg masses were field collected and returned to the laboratory, where emerging parasitoids were identified to species. In addition, 2,512 laboratory-reared E. servus eggs and 230 P. maculiventris eggs were placed as sentinels into crop fields and collected after 7 d, and parasitoid or stink bug emergence was recorded. Four species of hymenopteran parasitoids in the family Scelionidae were recovered from stink bug eggs: Telenomus podisi Ashmead, Trissolcus basalis Wollaston, Trissolcus edessae Fouts, and Trissolcus euschisti Ashmead. In addition, one parasitoid in the family Mymaridae (Hymenoptera) was recovered. Parasitism rates were highest in E. servus with 89.7 and 49.2% of egg masses and individual eggs parasitized, respectively. The predominant parasitoid species was T. podisi.

Background Mass drug administration (MDA) programs have dramatically reduced lymphatic filariasis (LF) incidence in many areas around the globe, including American Samoa. As infection rates decline and MDA programs end, efficient and sensitive methods for detecting infections are needed to monitor for recrudescence. Molecular methods, collectively termed ‘molecular xenomonitoring,’ can identify parasite DNA or RNA in human blood-feeding mosquitoes. We tested mosquitoes trapped throughout the inhabited islands of American Samoa to identify areas of possible continuing LF transmission after completion of MDA. Methodology/Principle Findings Mosquitoes were collected using BG Sentinel traps from most of the villages on American Samoa's largest island, Tutuila, and all major villages on the smaller islands of Aunu'u, Ofu, Olosega, and Ta'u. Real-time PCR was used to detect Wuchereria bancrofti DNA in pools of ≤20 mosquitoes, and PoolScreen software was used to infer territory-wide prevalences of W. bancrofti DNA in the mosquitoes. Wuchereria bancrofti DNA was found in mosquitoes from 16 out of the 27 village areas sampled on Tutuila and Aunu'u islands but none of the five villages on the Manu'a islands of Ofu, Olosega, and Ta'u. The overall 95% confidence interval estimate for W. bancrofti DNA prevalence in the LF vector Ae. polynesiensis was 0.20–0.39%, and parasite DNA was also detected in pools of Culex quinquefasciatus, Aedes aegypti, and Aedes (Finlaya) spp. Conclusions/Significance Our results suggest low but widespread prevalence of LF on Tutuila and Aunu'u where 98% of the population resides, but not Ofu, Olosega, and Ta'u islands. Molecular xenomonitoring can help identify areas of possible LF transmission, but its use in the LF elimination program in American Samoa is limited by the need for more efficient mosquito collection methods and a better understanding of the relationship between prevalence of W. bancrofti DNA in mosquitoes and infection and transmission rates in humans., Author Summary Lymphatic filariasis (LF), a mosquito-borne parasitic disease, has been targeted for elimination in many countries since the introduction of mass drug administration (MDA) programs using two-drug combinations along with improved diagnostic methods. Sensitive molecular methods detecting parasite DNA in pools of mosquitoes, along with efficient mosquito collection methods, can help identify sites of continuing LF transmission that may require further treatment after MDA has eliminated transmission in most areas. We tested mosquitoes from villages throughout American Samoa after the conclusion of a series of annual MDAs. Widespread but low prevalence of parasite DNA in mosquitoes from two of the five islands suggested continued occurrence of LF. In this study, parasite DNA detection in mosquitoes helped identify areas where human infections exist and additional treatment may be needed. In the future, development of more efficient mosquito collection methods for local species would facilitate larger sample sizes and more precise estimates of prevalence. In addition, developing a better understanding of the epidemiological significance of parasite DNA prevalence in the local mosquitoes will increase the operational value of those estimates for LF elimination programs.

Four quartz, orthogonal, cylindrical mirror pairs, two of which are coated with nickel, image the x‐ray emission from laser fusion targets on hard film with a magnification of 3. K‐edge filters used in conjunction with the mirror pairs permit us to take simultaneous pictures in four energy bands between 0.7 and 3.5 keV. We have measured microscope resolution, mirror reflection efficiency, and film sensitivity and used them to deduce the absolute emissivity and spectral characteristics of various laser fusion targets. This instrument is now used routinely for studying laser‐generated plasmas at Lawrence Livermore Laboratory.

Two dyes highly selective for phospholipids, Luxol Fast Blue ARN and Rhodamine 6G, were applied to freshly-prepared human platelets under a variety of conditions. Various substances which promote platelet aggregation were studied for their effects on (a) platelet uptake of these dyes and (b) platelet aggregation as measured by a new filtration technic.11 Results indicated that: (1) three substances which promote platelet aggregation (dextran, ADP, and sodium stearate) bring about parallel increases in the uptake of the dyes; (2) environmental conditions that enhance aggregation, such as increased temperature or decreased pH, increased the uptake of Luxol ARN, suggesting increased exposure of phospholipids at the plate'et surface. These and other findings indicate a possible direct relationship between cellular aggregation and the availability of surface phospholipids, with the latter exerting aggregative forces primarily through their hydrophobic bonding groups.

SummaryData have been presented on the in vitro effects of human chylomicra, low-density human plasma lipoproteins, and partially purified preparations of various phospholipids on human plasma euglobulin lysis. Euglobulin lysis was found to be accelerated by preparations of mixed soybean phospholipids (aso-lectin), cephalin, phosphatidyl inositol, phophatidyl serine and phosphatidyl ethanolamine. In contrast, it was found to be inhibited by preparations of human chylomicra, low-density human plasma liproproteins and lecithin. Inhibition of euglobulin lysis produced by any of these three agents could be diminished or completely overcome by the simultaneous presence of suitable levels of any one of the accelerating agents. In all cases studied, both inhibitory and accelerating effects were observed to be concentration-dependent. Evidence has been obtained to suggest that in the case of the accelerating agents the observed increased rate of euglobulin lysis is not a direct effect on lysis itself, but rather is due to more complete precipitation of plasminogen in the presence of these substances. On the other hand, it appears that the inhibitory effects observed are not related to the extent of plasminogen precipitation, but are actually true inhibitions of euglobulin lysis. The possible clinical significance of some of these observations has been briefly discussed.

Thrombin, usually regarded as a trypsin-like enzyme capable of hydrolyzing only esters of the amino acids arginine and lysine, was found to hydrolyze certain other amino acid esters which are considered specific chymotrypsin substrates. L-Phenylalanine methyl ester inhibited the activation of purified bovine prothrombin by autoprothrombin C, Ac-globulin, phospholipid, and calcium. It was subsequently shown that thrombin is capable of hydrolyzing L-phenylalanine methyl ester or L-tyrosine ethyl ester. This activity developed simultaneously with fibrogen clotting activity during activation of purified bovine prothrombin in 25% sodium citrate solutions. Moreover, the activity was closely associated with clotting activity on subsequent chromatography on DEAE-cellulose and Amberlite IRC-50 resin columns. All preparations of bovine thrombin, representing a wide range of purity, which have been examined, exhibited this hydrolyzing activity toward L-phenylalanine methyl ester. Further evidence linking this esterase activity with fibrinogen clotting activity was obtained when both activities were inhibited by 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate, an inhibitor of chymotrypsin.

SummarySince Ac-globulin (factor V) is involved in the formation of prothrombin activator, its ability to complex with phospholipids was studied. Purified bovine Ac-globulin was complexed to asolectin, there being presumably a fixed number of binding sites on the phospholipid micelle for Ac-globulin. In contrast to the requirement for calcium ions in the formation of complexes between asolectin and autoprothrombin C, calcium ions were not required for complex formation between asolectin and Ac-globulin to occur ; in fact, the presence of calcium prevented complex formation occurring, the degree of inhibition being dependent on the calcium concentration. By treating isolated, pre-formed aso- lectin-Ac-globulin complexes with calcium chloride solutions, Ac-globulin could be recovered in a much higher state of purity and essentially free of asolectin.Complete activators were formed by first preparing the asolectin-calcium- autoprothrombin C complex and then reacting the complex with Ac-globulin. A small amount of this product was very effective as an activator of purified prothrombin without further addition of calcium or any other cofactor. If the autoprothrombin C preparation used to prepare the complex was free of traces of prothrombin, the complete activator was stable for several hours at room temperature. Stable preparations of the complete activator were centrifuged, resulting in the sedimentation of most of the activity. Experimental evidence also indicated that activator activity was highest when autoprothrombin C and Ac-globulin were complexed to the same phospholipid micelle, rather than when the two clotting factors were complexed to separate micelles. These data suggested that the in vivo prothrombin activator may be a sedimentable complex composed of a thromboplastic enzyme, calcium, Ac-globulin and phospholipid.

Various physiologic aspects of the tendency toward intravascular clotting have been presented. The discussion includes comments on the lack of methods for anticipating intravascular clotting; the mechanism of blood coagulation; the effects of physical factors, drugs and endocrine influences on the clotting mechanism; the increased tendency to thrombosis in certain clinical states; the influence of lipids on the clotting mechanism; and the possible relation of formation and dissolution of clots to atherogenesis.

SummaryIn 34 patients exhibiting various clinical manifestations of atherosclerosis, 14 diabetic, 20 nondiabetic, abnormally high plasma lipid levels were observed to be depressed, in many instance...

SummaryCrude and partially purified phospholipid preparations have been studied for their effects on a) the activation of purified human plasminogen by streptokinase and b) the activity of plasmin resulting from such activation. Plasmin activity has been measured as BAMe esterase, caseinolytic, and fibrinolytic activities.Plasmin BAMe esterase activity was significantly enhanced by phosphatidyl inositol and phosphatidyl serine but only slightly by phosphatidyl ethanolamine. Preparations of asolectin and cephalin, although not having any effect on plasmin BAMe esterase activity per se, did appear to increase plasminogen activation by streptokinase. None of the above-mentioned effects was observed when plasmin caseinolytic activity was measured. The phospholipid preparation having the greatest effect on plasmin BAMe esterase activity, phosphatidyl inositol, also exhibited an effect on plasmin fibrinolytic activity. With both BAMe esterase and fibrinolytic activities the effects produced by the phospholipid materials were concentration dependent and, in the case of fibrinolytic activity, increased concentrations beyond the optimum level resulted in a gradual diminution in activity and eventual inhibition.

TAMe esterase activity levels have been determined on a) purified coagulation factors essential for thromboplastin (TPN) formation, b) various intermediate products formed in the presence of calcium and phospholipid, and c) complete blood thromboplastin. The level of esterase activity was found to increase as TPN formation proceeded through various intermediate stages to the final active product. The esterase activities of intermediate products I and II were practically completely inhibited by soybean trypsin inhibitor (SBTI), whereas that of blood thromboplastin was inhibited only partially. Interaction of product II with plasma Ac-globulin resulted in the most marked increase in esterase activity. The observations made suggest that this increased and SBTI-insensitive activity is not due to the presence of either thrombin or serum Ac-globulin (factor VI). It has been concluded that the observed TAMe esterase activity is due to blood thromboplastin itself and that the latter resembles Milstone's thrombokinase.

SummaryThe total platelet cofactor activity in plasma and the platelet cofactor II activity in serum was measured. The normal variations are high. Some individuals have less serum platelet cofactor II than found in certain cases of PTC “deficiency”; and when the serum platelet cofactor II concentration was reduced to zero with the use of anticoagulants, there was no bleeding tendency observed. With the use of Sintrom and phenylindanedione, the total platelet cofactor activity of plasma was reduced and the platelet cofactor II activity of serum was reduced to near zero. With the latter drug platelet cofactor II of serum was still low 10 days after the drug was withdrawn. With Sintrom given intermittently the fluctuations in prothrombin concentration are noticeably more rapid than the changes in platelet cofactor II. In a preliminary study of other drugs, there were indications that platelet cofactor II concentration is not altered with some anticoagulants even though the prothrombin concentration is reduced. Apparently, the platelet cofactor II changes which occur are characteristic for each anticoagulant. The platelet cofactor I levels of the plasma are not appreciably, and most likely not at all altered by the drugs studied.

Phosphoethanolamine and phosphoserine were studied for their in vitro effects on various phases of the blood coagulation mechanism. When added to freshly drawn, normal human blood both substances exhibit marked anticoagulant characteristics. When added to normal human plasma in the presence of either brain extract thromboplastin or Russell viper venom they produce an inhibition of clot formation which becomes more pronounced with increasing concentration. The effects observed appear to be due to an interference with thrombin formation rather than to an inhibition of the thrombin fibrinogen reaction. Evidence has been obtained which suggests that, depending upon their concentration, phosphoethanolamine and phosphoserine may inhibit either the formation of a prothrombin-converting principle only or inhibit, in addition, the activity of this principle as well.

Summary1. The presence in versene-col-lected, freshly prepared human platelets of a number of active dehydrogenase systems has been demonstrated. 2. Platelets can be lysed readily by various chemical and physical means, the resulting preparations being homogeneous and opalescent, but completely lacking in dehydrogenase activity. Evidence has been obtained to indicate that platelets have to be morphologically intact for dehydrogenase systems to be active. 3. The dehydrogenase systems present in platelets are activated by sulfhydryl-containing substances, the most marked effects of those studied being produced by cysteine and reduced glutathione. 4. The addition to platelets of sulfhydryl-oxidizing or mercaptide-forming agents results in platelet destruction apparently different in nature from that brought about by lysing agents not reacting with sulfhydryl groups. 5. Preliminary indications are that platelet destruction occurring during storage can be reduced by sulfhydryl-containing substances or environm...

Thrombin formation has been shown to be inhibited by oxidized glutathione and other sulfhydryl-oxidizing agents. This effect is observed with purified bovine prothrombin and with prothrombin as present in human plasma. It is different in nature from a similar inhibition brought about by sulfhydryl-containing (reducing) substances. Experiments with purified clotting factors and a variety of plasma and serum preparations have been carried out in order to elucidate the nature of the inhibition produced by SH-oxidizing substances. The results obtained indicate that thrombin formation is inhibited by these reagents as a result of their reaction with Ac-globulin sulfhydryl groups leading to partial or complete inactivation of this accelerator.

The primary research areas were the following: (1) contribute x-ray diagnostic, experimental, and data reduction and analysis support for the Novette DANTE x-ray spectrometer experiments. This effort was expanded to improve the overall quality of the Novette database; (2) experimental and calculational characterization of the x-ray imaging properties of an ellipsoidal x-ray collection optic serving as a sensitivity enhancing component of the Transmission Grating Streak Spectrometer; (3) performance simulation of the x-ray dispersion properties of candidate x-ray laser cavity, normal incidence end-mirror optics; (4) contribute x-ray diagnostic, experimental, and data reduction and analysis support for the Novette Henway crystal spectrometer and the MCPIGS microchannel plate intensified grazing incident spectrometer experiments; and (5) perform a technical performance vs cost evaluation of commercially available hardware required to perform the NOVA neutron time-of-flight experiments.

Layered synthetic microstructures have been built and tested for use as medium-resolution x-ray diffraction monochromators, in the 1 to 10 angstrom wavelength region. They can be employed to good advantage in spectrometry and imaging instruments that are used to determine the nature of the x-ray emission of high-temperature plasmas. When the micro-structures are used in spectrometers, we find that they gather much more light than natural crystals and are not troubled by high order diffraction response, yet have better spectral resolution than that provided by spectrometer channels formed by Ross filter or filter/fluorescer techniques. For use in imaging instruments such as the grazing-incidence reflection Kirkpartick-Baez microscope, the micro-structures provide high reflectivity at wavelengths shorter than the practical limit of total external reflection. We present calibration data that describes the diffraction properties and piece-to-piece uniformity of microstructures built especially for use in the 1 to 10 angstrom region. We also describe in detail two instruments that are to be used at the Shiva laser system to determine the spectral and spatial distributions of x-rays radiated by inertial confinement fusion targets.

The design of an active readout x-ray diffraction crystal spectrometer (HW-1024) for four key Pulsed Plasma Source (PRS) missions has been investigated. This active readout capability is installable into existing film-recording spectrometers, (HW-1000) and compatible with PRS facility computer resources. Three field retrofittable packages, detector, digital interface and control/DAS software, provide the active readout capability. Keywords: Active readout x-ray spectrometer; Diffraction crystals; Digital interface module.

This is a second-generation report on the characterization of laser-produced x-ray backlighting line sources. Previous work1-3 concentrated on the production of Au M(~2.5-keV), Ti K(~4.75-keV), Ni K (7.7-keV), and Zn K(8.6-keV) lines as a function of laser pulse length and intensity at λ L = 1.06 and 0.53 µm. Yaakobi et al.4 recently reported a similar characterization of K x-ray line emitters. They note that a factor of 10 or more increase in the line production efficiency (compared to λ l = 1.06-µm data) can be obtained when using a laser of wavelength λ L =0.35 µm. With the exception of lines from Au M band radiation, our present work does not substantiate their result. We observe a significantly less increase in production efficiency as a function of decreasing laser wavelength.

Summary1. Incubation of freshly prepared human platelets with a variety of sulfhydryl inhibitors results in increased rate of platelet breakdown. 2. In all cases studied the effects of inhibitors can be decreased in extent by suitable concentrations of SH-containing substances such as cysteine or reduced glutathione. 3. Results obtained suggest a direct relationship between platelet sulfhydryl groups and platelet structure. The possible link of this relationship to platelet metabolism is briefly discussed.