Deficiency for scavenger receptors Stabilin-1 and Stabilin-2 leads to age-dependent renal and hepatic depositions of fasciclin domain proteins TGFBI and Periostin in mice

Stabilin-1 (Stab1) and Stabilin-2 (Stab2) are two major scavenger receptors of liver sinusoidal endothelial cells that mediate removal of diverse molecules from the plasma. Double-knockout mice (Stab-DKO) develop impaired kidney function and a decreased lifespan, while single Stabilin deficiency or therapeutic inhibition ameliorates atherosclerosis and Stab1-inhibition is subject of clinical trials in immuno-oncology. Although POSTN and TFGBI have recently been described as novel Stabilin ligands, the dynamics and functional implications of these ligands have not been comprehensively studied. Immunofluorescence, Western Blotting and Simple Western™ as well as in situ hybridization (RNAScope™) and qRT-PCR were used to analyze transcription levels and tissue distribution of POSTN and TGFBI in Stab-KO mice. Stab-POSTN-Triple deficient mice were generated to assess kidney and liver fibrosis and function in young and aged mice. TGFBI and POSTN protein accumulated in liver tissue in Stab-DKO mice and age-dependent in glomeruli of Stabilin-deficient mice despite unchanged transcriptional levels. Stab-POSTN-Triple KO mice showed glomerulofibrosis and a reduced lifespan comparable to Stab-DKO mice. However, alterations of the glomerular diameter and vascular density were partially normalized in Stab-POSTN-Triple KO. TGFBI and POSTN are Stabilin-ligands that are deposited in an age-dependent manner in the kidneys and liver due to insufficient scavenging in the liver. Functionally, POSTN might partially contribute to the observed renal phenotype in Stab-DKO mice. This study provides details on downstream effects how Stabilin dysfunction affects organ function on a molecular and functional level.

Transcriptome dataset from Solanum lycopersicum L. cv. Micro-Tom; wild type and two mutants of INDOLE-ACETIC-ACID (SlIAA9) using long-reads sequencing oxford nanopore technologies

OBJECTIVE

Tomatoes are the most widely consumed fruit vegetable and are relatively easy to cultivate. However, an increase in temperature causes some plants to respond with a decrease in fruit production. So, it is necessary to develop plants resistant to extreme temperature changes. The tomato cv. Micro-Tom has genetic variations in the gene of INDOLE-ACETIC-ACID, namely SlIAA9-3 and SlIAA9-5. However, the genetic information regarding the full-length transcript of the gene from this type of tomato plant is unknown. Therefore, this study aimed to determine the full-length transcript of the genes of these three types of tomatoes using long-reads sequencing technology from Oxford Nanopore.

DATA DESCRIPTION

The total RNA from three types of Micro-Tom was isolated with the RNeasy PowerPlant Kit. Then, the RNA sequencing process used PCR-cDNA Barcoding kit - SQK-PCB109 and continued with the processing of raw reads based on the protocol from microbepore protocol ( https://github.com/felixgrunberger/microbepore ). The resulting raw reads were 578 374, 409 905, and 851 948 for wildtype, iaa9-3, and iaa9-5, respectively. After obtaining cleaned reads, each sample was mapped to the tomato reference genome (S. lycopersicum ITAG4.0) with the Minimap2 program. In particular, 965 genes were expressed only in the iaa9-3 mutant, and 2332 genes were expressed only in the iaa9-5 mutant. Whereas in the wild type, 1536 genes are specifically expressed. In cluster analysis using the heatmap analysis, separate groups were obtained between the wild type and the two mutants. This proves an overall difference in transcript levels between the wild type and the mutants.

Dataset from de novo transcriptome assembly of Myristica fatua leaves using MinION nanopore sequencer

Myristica fatua is a tropical fruit tree species originating from Indonesia. Very few genomic resources are available for the species. We developed a full-length transcriptome assembly using long-read sequencing (MinION Nanopore technology) and produced 4.3 million reads (3.5 G of bases). The assembled full-length transcript was constructed using the RATTLE program and assembled 21,098 transcripts. The transcript ranged from 201 - 14,174 bp, and N50 was 2,017 bp. The transcripts were annotated with the UNIPROT database using BlastX. The functional annotation was performed using Blast2go software. The 8,445 microsatellite motif-containing contigs were identified. The raw reads are deposited in the ENA (European Nucleotide Archive) with ENA experiment accession number ERX6798613.

Targeting of Scavenger Receptors Stabilin-1 and Stabilin-2 Ameliorates Atherosclerosis by a Plasma Proteome Switch Mediating Monocyte/Macrophage Suppression

BACKGROUND

Scavenger receptors Stabilin-1 (Stab1) and Stabilin-2 (Stab2) are preferentially expressed by liver sinusoidal endothelial cells. They mediate the clearance of circulating plasma molecules controlling distant organ homeostasis. Studies suggest that Stab1 and Stab2 may affect atherosclerosis. Although subsets of tissue macrophages also express Stab1, hematopoietic Stab1 deficiency does not modulate atherogenesis. Here, we comprehensively studied how targeting Stab1 and Stab2 affects atherosclerosis.

METHODS

ApoE-KO mice were interbred with Stab1-KO and Stab2-KO mice and fed a Western diet. For antibody targeting, Ldlr-KO mice were also used. Unbiased plasma proteomics were performed and independently confirmed. Ligand binding studies comprised glutathione-S-transferase-pulldown and endocytosis assays. Plasma proteome effects on monocytes were studied by single-cell RNA sequencing in vivo, and by gene expression analyses of Stabilin ligand-stimulated and plasma-stimulated bone marrow-derived monocytes/macrophages in vitro.

RESULTS

Spontaneous and Western diet-associated atherogenesis was significantly reduced in ApoE-Stab1-KO and ApoE-Stab2-KO mice. Similarly, inhibition of Stab1 or Stab2 by monoclonal antibodies significantly reduced Western diet-associated atherosclerosis in ApoE-KO and Ldlr-KO mice. Although neither plasma lipid levels nor circulating immune cell numbers were decisively altered, plasma proteomics revealed a switch in the plasma proteome, consisting of 231 dysregulated proteins comparing wildtype with Stab1/2-single and Stab1/2-double KO, and of 41 proteins comparing ApoE-, ApoE-Stab1-, and ApoE-Stab2-KO. Among this broad spectrum of common, but also disparate scavenger receptor ligand candidates, periostin, reelin, and TGFBi (transforming growth factor, β-induced), known to modulate atherosclerosis, were independently confirmed as novel circulating ligands of Stab1/2. Single-cell RNA sequencing of circulating myeloid cells of ApoE-, ApoE-Stab1-, and ApoE-Stab2-KO mice showed transcriptomic alterations in patrolling (Ccr2^-/Cx3cr1⁺⁺/Ly6C^lo) and inflammatory (Ccr2⁺/Cx3cr1⁺/Ly6C^hi) monocytes, including downregulation of proatherogenic transcription factor Egr1. In wildtype bone marrow-derived monocytes/macrophages, ligand exposure alone did not alter Egr1 expression in vitro. However, exposure to plasma from ApoE-Stab1-KO and ApoE-Stab2-KO mice showed a reverted proatherogenic macrophage activation compared with ApoE-KO plasma, including downregulation of Egr1 in vitro.

CONCLUSIONS

Inhibition of Stab1/Stab2 mediates an anti-inflammatory switch in the plasma proteome, including direct Stabilin ligands. The altered plasma proteome suppresses both patrolling and inflammatory monocytes and, thus, systemically protects against atherogenesis. Altogether, anti-Stab1- and anti-Stab2-targeted therapies provide a novel approach for the future treatment of atherosclerosis.

[Typical liability damages of the upper extremities in childhood and their evaluation]

Legal appraisals of possible treatment errors in childhood and adolescence are rare, often refer to the treatment of trauma of the upper limbs and are frequently recognized. From the activity of the first author as an expert witness 31 expert opinions (25%) referred to the upper limbs. Supracondylar humeral fractures, radius neck fractures, radial condyle fractures and distal radius fractures were predominant. A primary treatment error was determined in 14 patients and a secondary error in 7 patients. This corresponds to a recognition rate of 68%. The aim of this study was the reflection and the development of a prevention strategy. Insufficient recognition of instability (radial condyle), inadequate reduction and inadequate stabilization (radius neck, supracondylar) as well as untreated malalignments and secondary dislocations (wrist) were the main reproaches. Poor communication and deficient documentation often aggravate the situation. Working along clear algorithms can help to avoid legal proceedings and assignment of guilt.

The right supraclavicular fossa ultrasound view for correct catheter tip positioning in right subclavian vein catheterisation: a prospective observational study

Central venous catheter misplacement is common (approximately 7%) after right subclavian vein catheterisation. To avoid it, ultrasound-guided tip navigation may be used during the catheterisation procedure to help direct the guidewire towards the lower superior vena cava. We aimed to determine the number of central venous catheter misplacements when using the right supraclavicular fossa ultrasound view to aid guidewire positioning in right infraclavicular subclavian vein catheterisation. We hypothesised that the incidence of catheter misplacements could be reduced to 1% when using this ultrasound technique. One -hundred and three adult patients were prospectively included. After vein puncture and guidewire insertion, we used the right supraclavicular fossa ultrasound view to confirm correct guidewire J-tip position in the lower superior vena cava and corrected the position of misplaced guidewires using real-time ultrasound guidance. Successful catheterisation of the right subclavian vein was achieved in all patients. The guidewire J-tip was initially misplaced in 15 patients, either in the ipsilateral internal jugular vein (n = 8) or in the left brachiocephalic vein (n = 7). In 12 patients it was possible to adjust the guidewire J-tip to a correct position in the lower superior vena cava. All ultrasound-determined final guidewire J-tip positions were consistent with the central venous catheter tip positions on chest X-ray. Three out of 103 catheters were misplaced, corresponding to an incidence (95%CI) of 2.9 (0.6-8.3) %. Although the hypothesis could not be confirmed, this study demonstrated the usefulness of the right supraclavicular fossa ultrasound view for real-time confirmation and correction of the guidewire position in right infraclavicular subclavian vein catheterisation.

Counter-regulation of the ligand-receptor pair Leda-1/Pianp and Pilrα during the LPS-mediated immune response of murine macrophages

Liver endothelial differentiation-associated protein-1 (Leda-1/Pianp) is a type-I-transmembrane protein that is able to bind and activate immune inhibitory receptor Pilrα. Here we show that Leda-1/Pianp is strain-specifically expressed in lymphoid organs and macrophages of Th2-prone BALB/c mice but not of Th1-prone C57BL/6J mice. LPS stimulation of BALB/c bone marrow-derived macrophages (BMM) and macrophage-like Raw 264.7 cells conversely regulated Leda-1/Pianp and Pilrα expression. Pilrα induction was caused by LPS-mediated transcriptional modulation and increased mRNA expression. On the other hand, the LPS-mediated decline of Leda-1/Pianp expression was the result of proteolytic degradation by matrix metalloproteinases. In summary, these findings demonstrate that counter-regulation of the ligand-receptor pair Leda-1/Pianp and Pilrα is part of the complex innate immune response of macrophages and its genetically determined strain-specific modulation.

Proteolytic cleavage of LEDA-1/PIANP by furin-like proprotein convertases precedes its plasma membrane localization

Liver endothelial differentiation-associated protein-1 (LEDA-1/PIANP) is a type-I-transmembrane protein first identified by us as a putative junctional protein in liver sinusoidal endothelial cells. Others have shown that LEDA-1/PIANP binds and activates immune inhibitory receptor PILRα in trans, a process that requires sialidation of LEDA-1/PIANP. Here we show that LEDA-1/PIANP is subject to O-glycosylation and sialidation as demonstrated in brain tissue as well as in LEDA-1 expressing cell lines by using anti-LEDA-1/PIANP C-terminal antibodies. In addition, analysis of LEDA-1/PIANP processing with His-tags inserted at different positions in the extracellular domain revealed that multiple steps of proteolytic cleavage occur during maturation of the protein. Proteolytic cleavage between aa59 and aa83 preceded sorting of the protein to the plasma membrane. Deletion of aa75-79 and inhibition with Furin inhibitor I confirmed that LEDA-1/PIANP is processed by a Furin-like proprotein convertase. In summary, these findings show that Furin-like proprotein convertase-dependent processing precedes plasma membrane localization of LEDA-1/PIANP that is a pre-requisite of functional receptor-ligand interactions in vitro and in vivo.

Magnetically tunable optical absorbance in a colloidal system

We study the optical absorbance from a magnetically arranged colloidal structure, and investigate the possibility of creating a magnetically controlled optical sensor using this system. The colloids form chains when exposed to an external magnetic field, which tend to collapse and form a more random particle arrangement when the field is removed. We show that a small magnetic field is able to change the sensor's reflection coefficient by more than 30%, and investigate in detail the relaxation mechanism when the field is turned off.

Crystallography of dispersed liquid crystalline phases studied by cryo-transmission electron microscopy

Low molecular weight surfactants, for example monoglycerides and phospholipids, form a multitude of self-assembled structures, such as inverted cubic or hexagonal mesophases, if brought into contact with water/oil. These mesophases can be dispersed in water using adequate surface-active materials such as low molecular weight surfactants or surface active polymers. In order to use such mesophase particles for incorporating drugs and aromas, it is essential to determine their internal crystallographic structure and to understand their mechanism of stabilization. Cryo-transmission electron microscopy was used to investigate the internal structure of different dispersed particles at various temperatures and oil contents. It is shown here that cryo-transmission electron microscopy, in combination with fast Fourier transform and tilting experiments, is effective in obtaining information on crystallographic structure, space group and morphology of particles with reversed bicontinuous cubic and hexagonal structures. In particular, using the presence or the absence of the {111} reflections and viewing the same particle under different axes of observation allows one to discriminate between the Im3m and Pn3m space groups. A major advantage of cryo-transmission electron microscopy is the ability to analyse single particles. This allows the identification of particles present at very low concentrations and the coexistence of particles with different internal self-assembly structures. With this technique we have obtained strong evidence for the presence of two cubic internal self-assembly structures with different space groups within the same dispersion. In addition, we found that cryo-transmission electron microscopy combined with tilting experiments enables the analysis of internal particle morphology, allowing the discussion of mechanisms for hexosome stabilization.

Cell wall modification in grapevine cells in response to UV stress investigated by atomic force microscopy

Despite cell wall reinforcement being a well-known defence mechanism of plants, it remains poorly characterized from a physical point of view. The objective of this work was to further describe this mechanism. Vitis vinifera cv Gamay cells were treated with UV-light (254 nm), a well-known elicitor of defence mechanisms in grapevines, and physical cell wall modifications were observed using the atomic force microscopy (AFM) under native conditions. The grapevine cell suspensions were continuously observed in their culture medium from 30 min to 24h after elicitation. In the beginning, cellulose fibrils covered by a matrix surrounded the control and treated cells. After 3 h, the elicited cells displayed sprouted expansions around the cell wall that correspond to pectin chains. These expansions were not observed on untreated grapevine cells. The AFM tip was used to determine the average surface elastic modulus of cell wall that account for cell wall mechanical properties. The elasticity is diminished in UV-treated cells. In a comparative study, grapevine cells showed the same decrease in cell wall elasticity when treated with a fungal biotic elicitor of defence response. These results demonstrate cell wall strengthening by UV stress.

Amylopectin: a major component of the residual body in Cryptosporidium parvum oocysts

Amylopectin is used for carbohydrate storage in different life-stages of a number of apicomplexan parasites. We have performed an ultrastructural analysis of amylopectin granules from the oocyst residual body and sporozoites of Cryptosporidium parvum. Amylopectin granules were studied in situ and after isolation from 'French' press disrupted parasites, by conventional transmission electron microscopy (TEM) of sectioned oocysts and various negative staining and cryoelectron microscopy techniques. Within the membrane-enclosed oocyst residuum large amylopectin granules (0.1-0.3 microm) can be found besides a characteristic large lipid body and a crystalline protein inclusion. Smaller granules were detected in sectioned sporozoites. Negative staining of isolated amylopectin granules revealed some ultrastructural features not readily visible in sectioned material. The large amylopectin granules had a smooth surface with a 'ball of string'-like inner structure. Granules isolated from sporozoites were more irregularly shaped and showed a rod-like particulate composition. With the exception of alpha-amylase, which led to some degree of damage of the surface of the particles, treatment of amylopectin granules with other glycohydrolases had little effect on the overall structure. However, granules adhered to one another. Only when the granules were boiled did the 'ball of string' structure gradually dissolve.

Vitrification of cryoelectron microscopy specimens revealed by high-speed photographic imaging

Cryoelectron microsopy is a widely used technique to observe biological material in an almost physiological, fully hydrated state. The sample is prepared for electron microsopy observation by quickly reducing its temperature to -180 degrees C. The high-speed cooling induces the formation of vitreous water, which preserves the sample conformation. However, the way vitrification occurs is still poorly understood. In order to better understand the phenomenon, we have used a stroboscopic device to visualize the interaction between the electron microscopy grid and the cryogen. By blocking the free fall of the plunger once the grid has penetrated the coolant by half its diameter, we have elucidated the way in which vitrification propagates. The findings were confirmed by numerical simulation. In addition, according to our observations, we now present an alternative way to prepare vitreous specimens. This new method, with the grid parallel to the liquid cryogen surface, decreases evaporation from the sample during its free fall towards the coolant and at the same time achieves a more uniform vitrification over the entire surface of the specimen.

Can alcohol price policies be used to reduce drunk driving? Evidence from Canada

Drunk driving is one of the more serious negative consequences of alcohol consumption. Since consumption of alcohol is sensitive to the price of alcohol, and the occurrence of drunk driving is sensitive to the level of alcohol consumption, the possibility exists for alcohol pricing policies to be used to reduce drunk driving in the population. This paper reviews the evidence on this possibility in the literature and adds results based on data from the Canadian province of Ontario. Multiple regression analysis of time series data for Ontario from 1972 to 1990 indicate that, controlling for income, the proportion of young males in the population, changes in the minimum drinking age, and other confounding variables, increasing the price of alcohol has a significant effect in reducing alcohol-related motor vehicle accidents (elasticity = - 1.2, p < .05) and alcohol-related traffic offenses (elasticity = -0.50, p < .05). Overall, the evidence strongly supports the view that alcohol tax and pricing policies can be used to reduce the extent of drunk driving.

Do treatments and other interventions work? Some critical issues

A variety of interventions, both therapeutic and preventive, have been used to control, reduce or eliminate substance use and misuse and their attendant problems. Yet, despite years of ever more sophisticated and expensive ways of responding to the use and misuse of a variety of legal and illegal substances, addiction continues to be experienced as a major social problem that plagues users, their families and communities, therapists and clinicians, policymakers, and the public. In view of a recidivist treatment population and finite resources, this paper considers whether and to what extent treatments and other interventions used for planned interventions with alcohol- and drug-use related problems work. It examines both clinical treatment outcomes and broad-based population prevention interventions, and reviews their underlying rationales. Finally, it identifies a number of areas that must be addressed if we are to improve the situation. These areas include a lack of agreement on what is meant by the problem of "addictions," how successful interventions are to be defined and measured so that better interventions can be applied in the future, as well as integrating the processes of quality and appropriateness into the planning, implementation and assessment of effective, needed substance use intervention.

Transmission electron microscopical studies on some haemolymph proteins from the marine polychaete Nereis virens

The hexagonal bilayer haemoglobin molecule from Nereis virens has been investigated in a comparative study using several different negative stain electron microscopical specimen preparations (i.e. by conventional adsorption to continuous carbon support films, by the negative staining-carbon film technique and by negative staining across the holes of holey carbon support films with air-drying and rapid freezing/cryo-negative staining). The benefits and limitations of these different approaches are indicated, with the overall conclusion that negative staining with ammonium molybdate across holes creates the best possibilities for molecular imaging, and also has the potential for the creation of two-dimensional (2D) crystals/arrays at the fluid-air interface. Of the different negative staining procedures presented, cryo-negative staining reveals the greatest details of N. virens haemoglobin. This is exemplified by the direct visualisation of the central linker-assembly within the haemoglobin molecule, a structural feature less clearly defined by the other negative staining techniques. A discoidal lipoprotein molecule (diameter 30-60nm; thickness ca 8nm) has been detected in N. virens, which represents the first documented account of an annelid haemolymph lipoprotein. The biological implications of this lipoprotein for lipid transport remain to be established. The presence of a low concentration of ferritin molecules in N. virens haemolymph is also shown, assisted by the formation of small 2D ferritin arrays in negatively stained specimens prepared across holes.

The formation of empty shells upon pressure induced decapsidation of turnip yellow mosaic virus

The stability of turnip yellow mosaic virus (TYMV) was investigated under pressure, using solution neutron small angle scattering. Dissociation products were characterized by analytical ultracentrifugation and electron microscopy. At pH 6.0, TYMV remained unaffected by pressure, up to 260 Megapascals (MPa), the highest pressure reached in these experiments. At pH 8.0, TYMV remained unaffected by pressure up to 160 MPa, but decapsidated irreversibly above 200 MPa, giving rise to more and more empty shells upon increasing pressure. The organization of these empty shells was similar to that of the capsid of native virions, apart from the presence of a hole corresponding to the loss of a group of 5-8 coat protein subunits, through which the RNA may have escaped. At variance with other small isometric viruses, the capsid of TYMV never dissociated under pressure into subunits or small aggregates of subunits. This exceptional behavior of TYMV is probably due to the importance of van der Waals contacts and hydrogen bonds in the stability of its capsid.

Stilbene content of mature Vitis vinifera berries in response to UV-C elicitation

A method using HPLC analysis has been used to compare the level of resveratrol and its derivatives, piceid, pterostilbene and epsilon-viniferin, in grapevine berries of three Vitis vinifera varieties. The concentration of these compounds has been evaluated in healthy and Botrytis cinerea infected grape clusters, both in natural vineyard conditions and in response to UV elicitation.

Self-assembly of beta-amyloid 42 is retarded by small molecular ligands at the stage of structural intermediates

Assemblyof the amyloid-beta peptide (Abeta) into fibrils and its deposition in distinct brain areas is considered responsible for the pathogenesis of Alzheimer's disease (AD). Thus, inhibition of fibril assembly is a potential strategy for therapeutic intervention. Electron cryomicroscopy was used to monitor the initial, native assembly structure of Abeta42. In addition to the known fibrillar intermediates, a nonfibrillar, polymeric sheet-like structure was identified. A temporary sequence of supramolecular structures was revealed with (i) polymeric Abeta42 sheets during the onset of assembly, inversely related to the appearance of (ii) fibril intermediates, which again are time-dependently replaced by (iii) mature fibrils. A cell-based primary screening assay was used to identify compounds that decrease Abeta42-induced toxicity. Hit compounds were further assayed for binding to Abeta42, radical scavenger activity, and their influence on the assembly structure of Abeta42. One compound, Ro 90-7501, was found to efficiently retard mature fibril formation, while extended polymeric Abeta42 sheets and fibrillar intermediates are accumulated. Ro 90-7501 may serve as a prototypic inhibitor for Abeta42 fibril formation and as a tool for studying the molecular mechanism of fibril assembly.

Unexpected property of trehalose as observed by cryo-electron microscopy

Trehalose is an agent useful in maintaining the integrity of many biological systems submitted to various stresses. It is also presumed to improve specimen preparation for electron microscopy and to reduce beam damage. Here we study the effect of trehalose on the preparation and observation by cryo-electron microscopy of thin vitrified films of biological suspensions. We observe that trehalose, as compared to sucrose, can indeed reduce electron beam damage to biological particles, as determined from the dose necessary for the onset of bubbling. Surprisingly, we also find that the contrast of biological particles is higher in a vitrified solution of trehalose than in one of sucrose. This effect can be explained if the water evaporation during the specimen preparation is less in the presence of trehalose than with sucrose, but we do not yet understand the underlying reasons since the evaporation properties of both sugars are similar at a macroscopic level. We conclude that trehalose is truly a remarkable substance and that more investigation is needed in order to fully understand its properties, and that the addition of ca. 3-5% trehalose to biological suspensions is a simple and useful method to reduce commonly arising drying artefacts and water evaporation in the thin film vitrification method.

Changes in the phytoalexin content of various Vitis spp. in response to ultraviolet C elicitation

The phytoalexin production potential of three American Vitis species and that of three cultivars of Vitis vinifera were evaluated in response to UV-C irradiation. Time course changes in resveratrol, piceid, epsilon-viniferin, and pterostilbene contents were studied within 3 days after a short UV-C irradiation. Results show that the two major stilbenes accumulated as a response to UV-C elicitation are resveratrol and epsilon-viniferin, a resveratrol dehydrodimer, the concentration of both compounds usually reaching quantities >100 microgram/g of fresh weight. In contrast, piceid and pterostilbene were constantly produced in low quantities. Owing to the results obtained, the role of stilbene phytoalexins in the resistance of grapevines to diseases is discussed.

Polymorphism of turnip yellow mosaic virus empty shells and evidence for conformational changes occurring after release of the viral RNA. A differential scanning calorimetric study

Turnip yellow mosaic virus (TYMV) is a small isometric plant virus which decapsidates by releasing its RNA through a hole in the capsid, leaving behind an empty shell [R. E. F. Matthews and J. Witz, (1985) Virology 144, 318-327]. Similar empty shells (artificial top component, ATC) can be obtained by submitting the virions to various treatments in vitro. We have used differential scanning calorimetry, analytical sedimentation, and electron microscopy to investigate the thermodenaturation of natural empty shells (NTC, natural top component) present in purified virus suspensions, and of several types of ATCs. ATCs divided in two major classes. Those obtained by alkaline titration, by the action of urea or butanol behaved as NTC: their thermograms contained only one peak corresponding to the irreversible dissociation of the shells and the denaturation of the coat protein. The temperature of this unique transition varied significantly with pH, from 71 degrees C at pH 4.5 to 84 degrees C at pH 8.5. The thermograms of ATCs obtained by freezing and thawing, or by the action of high pressure, contained two peaks: shells dissociated first into smaller protein aggregates at 57 degrees C (at pH 5.0) to 61 degrees C (at pH 8.5), which denatured at the temperature of the unique transition of NTC. Shells obtained by heating virions to 55 degrees C at pH 7.6, changed conformation after the release of the viral RNA, as upon continuous heating to 95 degrees C, their thermograms were similar to those of the shells obtained by freezing and thawing, whereas after purification they behaved like NTC. Structural implications of these observations are discussed.

Characterization of a Pterostilbene Dehydrodimer Produced by Laccase of Botrytis cinerea

ABSTRACT In the interaction between grapevines and Botrytis cinerea, one of the main aspects of pathogenicity is fungal ability to degrade phytoalexins synthesized by the plant in response to infection. Laccase-like stilbene oxidase activity in liquid cultures of B. cinerea has been shown to be related to the decrease of phytoalexin concentrations. Recent research and results presented in this paper determined the chemical structure of a pterostilbene metabolite produced by B. cinerea. Study of degradation of pterostilbene that has just one free hydroxy phenyl group function allowed us to determine the oxidative dimerization process undergone by grapevine phytoalexins after B. cinerea infection. The phytopathological significance of this degradation process in the B. cinerea interaction has also been discussed.

Is community-based treatment an add-on or a substitution for hospital treatment of alcoholism? Some evidence from Canada

OBJECTIVES

This study determined whether the development of community treatment of alcohol problems acted as an add-on or a substitution for the utilization of inpatient hospital services in Ontario.

METHODS

Complex modelling and graphic analyses using econometric multiple regression techniques were performed on data for the 48 counties of Ontario (Canada) for the period 1972 to 1988, combining both cross-sectional and time series analysis.

RESULTS

After controlling for differences in alcohol consumption, in health care characteristics such as the supply of physicians or hospital occupancy rates, and in socioeconomic characteristics of the population, when community treatment became available, hospital utilization for the treatment of alcohol problems decreased and community services were substituting for hospital treatment. In addition, nonresidential services had an overall greater importance in producing this effect (elasticities at the mean of -0.11 to -0.14 depending on the region) than community-based residential treatment. The effect was larger in the southern than in the northern counties of Ontario. Testing of the modelling techniques showed statistically significant and satisfactory modelling of the forces at work.

CONCLUSIONS

Where community-based treatment was available, it was used in preference to inpatient hospital treatment; however, there may be a slightly more complex relationship present in the southern urban counties (which contain the larger metropolitan areas) than in the northern and southern rural counties..

Cholesterol-Streptolysin O Interaction: An EM Study of Wild-Type and Mutant Streptolysin O

We present transmission electron microscopical data from negatively stained specimens of cholesterol following interaction with the thiol-activated bacterial toxin streptolysin O (SLO) (wild-type and a number of cysteine substitution mutants), with and without chemical modification of the cysteine residues. Two experimental systems were used, one with an aqueous suspension of cholesterol microcrystals and the other with immobilized thin planar cholesterol crystals attached to a carbon film. In both systems the wild-type SLO and two cytolytically active mutants, Cys 530 --> Ala (C530A) and Ser 101 --> Cys (S101C), readily generated the characteristic SLO arc- and ring-like oligomers on the surface of cholesterol microcrystals and immobilized planar cholesterol crystals. An underlying array of bound toxin can sometimes be detected. In the presence of high concentrations of SLO monomer, extensive sheet-like networks of linked oligomers extend from the microcrystals. The SLO mutant Thr250 --> Cys (T250C), which also possesses a relatively high cytolytic activity, has been found to create ring-like toxin oligomers somewhat more slowly than wild-type SLO, but the linear monomolecular layer array of cholesterol-bound toxin is more readily detected. With mutant Asn402 --> Cys (N402C), which has approximately 10% cytolytic activity compared to wild-type SLO, the formation of ring-like oligomers is markedly reduced, with incomplete arcs and the parallel arrays predominating. Chemical modification of the functional cysteine groups of SLO mutants T250C and N402C completely inhibits the formation of toxin oligomers, but does not prevent the ability of these mutants to bind to cholesterol as a linear array. Such chemical modification is also known to abolish hemolysis/cytolysis. For both mutant T250C and N402C the parallel array of bound SLO adopts an orientation that appears to be determined by the underlying lattice of the crystalline cholesterol. The cholesterol-binding of biotinylated SLO mutant N402C was confirmed by labeling in suspension with 5-nm streptavidin-conjugated colloidal gold particles. Removal of the maltose-binding protein from the SLO fusion products increases the order of the monolayer array of biotinylated SLO bound to cholesterol crystals. Overall, our data support the concept that there is sterospecific binding of the SLO monomer to crystalline cholesterol bilayers, prior to oligomer formation. With the mutants tested, cysteine modification does not prevent binding to cholesterol, but subsequent release and oligomer formation are blocked. Copyright 1998 Academic Press.

Resveratrol Oxidation in Botrytis cinerea Conidia

ABSTRACT Observations using light microscopy showed that approximately 30% of Botrytis cinerea conidia treated with semi-lethal concentrations (i.e., 60 mug/ml) of the grapevine phytoalexin resveratrol possessed intracellular brown coloration. This coloration was never observed in the absence of resveratrol or in conidia treated with resveratrol together with sulfur dioxide (antioxidant compound) or sodium diethyldithiocarbamate (inhibitor of laccase action), suggesting that discoloration resulted from the laccase-mediated oxidation of resveratrol. Further studies using transmission electron microscopy enabled the observation of particular intravacuolar spherical vesicles and of granular material deposits along the tonoplast. These observations are likely to be related to the oxidation of resveratrol by an intracellular laccase-like stilbene oxidase of B. cinerea.

Cryo-negative staining

A procedure is presented for the preparation of thin layers of vitrified biological suspensions in the presence of ammonium molybdate, which we term cryo-negative staining. The direct blotting of sample plus stain solution on holey carbon supports produces thin aqueous films across the holes, which are routinely thinner than the aqueous film produced by conventional negative staining on a continuous carbon layer. Because of this, a higher than usual concentration of negative stain (ca. 16% rather than 2%) is required for cryo-negative staining in order to produce an optimal image contrast. The maintenance of the hydrated state, the absence of adsorption to a carbon film and associated sample flattening, together with reduced stain granularity, generates high contrast cryo-images of superior quality to conventional air-dry negative staining. Image features characteristic of unstained vitrified cryo-electron microscopic specimens are present, but with reverse contrast. Examples of cryo-negative staining of several particulate biological samples are shown, including bacteriophage T2, tobacco mosaic virus (TMV), bovine liver catalase crystals, tomato bushy stunt virus (TBSV), turnip yellow mosaic virus (TYMV), keyhole limpet hemocyanin (KLH) types 1 and 2, the 20S proteasome from moss and the E. coli chaperone GroEL. Densitometric quantitation of the mass-density of cryo-negatively stained bacteriophage T2 specimens before and after freeze-drying within the TEM indicates a water content of 30% in the vitreous specimen. Determination of the image resolution from cryo-negatively stained TMV rods and catalase crystals shows the presence of optical diffraction data to ca. 10 A and 11.5 A, respectively. For cryo-negatively stained vitrified catalase crystals, electron diffraction shows that atomic resolution is preserved (to better than 20 diffraction orders and less than 3 A). The electron diffraction resolution is reduced to ca. 10 A when catalase crystal specimens are prepared without freezing or when they are freeze-dried in the electron microscope. Thin vitrified films of TMV, TBSV and TYMV in the presence of 16% ammonium molybdate show a clear indication of two-dimensional (2-D) order, confirmed by single particle orientational analysis of TBSV and 2-D crystallographic analysis of TYMV. These observations are in accord with earlier claims that ammonium molybdate induces 2-D array and crystal formation from viruses and macromolecules during drying onto mica. Three-dimensional analysis of the TBSV sample using the tools of icosahedral reconstruction revealed that a significant fraction of the particles were distorted. A reconstruction from a subset of undistorted particles produced the characteristic T = 3 dimer clustered structure of TBSV, although the spikes are shortened relative to the structure defined by X-ray crystallography. The 20S proteasome, GroEL, catalase, bacteriophage T2, TMV, TBSV and TYMV all show no indication of sample instability during cryo-negative staining. However, detectable dissociation of the KLH2 oligomers in the presence of the high concentration of ammonium molybdate conforms with existing knowledge on the molybdate-induced dissociation of this molecule. This indicates that the possibility of sample-stain interaction in solution, prior to vitrification, must always be carefully assessed.

Transmission electron microscopy and scanning force microscopy of poly r(A-U) and poly r(A-U)-ethidium bromide

Transmission electron microscopy and scanning force microscopy of negative-stained, carbon-coated replica and mica-adsorbed preparations of 200 microM poly r(A-U) and 50 microM ethidium bromide/200 microM poly r(A-U) have been employed to evaluate ethidium-induced changes in poly r(A-U) topology. Poly r(A-U) alone exhibits elongated conformations 85-115 nm in length that possess a number of hairpin loops as well as single-stranded domains. While the double-stranded domains are found predominately at the base of the hairpin loops (diameter = 5-30 nm), other rod-like (presumably double-stranded) regions ranging from 25-80 nm in length are present in other portions of the poly r(A-U). In contrast with the poly r(A-U) alone, the EB/poly r(A-U) combination appears as a heterogeneous population of condensed structures whose lengths and widths vary from 12-88 nm and 15-45 nm, respectively. These conformational changes are due to a number of factors, including the displacement of ordered water surrounding the poly r(A-U) and charge shielding of the phosphate groups of the poly r(A-U) upon the binding of the ethidium.

Substance use and multiculturalism

This paper reviews intercultural variability of substance use behaviors, including availability of international statistics on consumption of alcohol and other drugs, as well as the use of drugs available locally only. Within a conceptual framework of intercultural relations, it considers the history of transcultural spread of substance use behaviors and possible reactions to the introduction of new drugs within a culture or jurisdiction, including illustrations of the "law of alien poisons." Although intercultural views of substance use have generally concentrated on majority groups' views of substance use in minority groups, minority and non-Western views of substance use need to be considered in the context of increasing international and intercultural communications that increase the rate at which substance use behaviors spread. Both Western and non-Western experiences with substance use and misuse must be taken into account so that better interventions can be developed to deal with addictions and other substance-related problems.

Does allowing the sale of wine in Quebec grocery stores increase consumption?

OBJECTIVE

To determine if allowing wine sales in corner grocery stores, beginning in 1978 for domestic Quebec wines and then in 1983 for imported wines, in addition to sales in government monopoly stores, led to an increase in alcohol consumption.

METHOD

Aggregate retail sales data for the period 1953 to 1990 were analyzed using econometric regression techniques. Time series (unit root) analysis and structural modeling were used to take into account the effect of price, income and other social, economic and demographic factors in order to determine the effect of factors underlying consumption behavior in both the long and short term.

RESULTS

In the post-intervention period, wine consumption continued along the rising trend established in the pre-intervention period, with an apparent shift in favor of domestic wine consumption. The increase in wine consumption was highest in the period immediately following privatization, but the increase eventually dampened down within a few years. There was no fundamental change in the responsiveness of wine consumption to price.

CONCLUSION

Our findings suggest that the level of wine consumption can be controlled through price changes when alcohol availability increases through increased sales outlets.

Temporal coupling between external auditory information and the phases of walking

The purpose of this study was to investigate the effects of an imposed external auditory constraint upon the temporal organization of walking. Ten subjects were videotaped walking normally (N) and with instructions to couple naturally, at mid-swing, or at toe-off to a metronome beat. Based upon an analysis of variance and post hoc Scheffé tests most temporal variables were not significantly different among conditions. The duration of swing phase was significantly different between natural coupling and toe-off. The deviation from the metronome beat was significantly different between the natural coupling and both mid-swing and toe-off. Subjects generally were not successful in achieving coupling during the latter conditions. Thigh and shank phase portraits were used to describe the system's organization to the external constraint.

Substance use as a measure of social integration for women of different ethnocultural groups into mainstream culture in a pluralist society: the example of Canada

Analysis of Canadian data from the 1989 National Alcohol and Drugs Survey was used to identify profiles of alcohol and other drug-using behaviors among Canadian women of different ethnic or cultural groups. The profile considered 110 different substance use variables including alcohol or drug type used, quantity, frequency, drinking or drug-taking circumstances, beverage preference, reasons for drinking or not drinking, and opinions regarding appropriate drinking or drug-taking behavior of Canadian women who described themselves as belonging to the "Canadian," French, English, German/Dutch, Irish, Scottish, Ukrainian/Polish, Italian/Portuguese, and "Other" (Chinese, Jewish, and "Other") ethnic or cultural groups. Alcohol, tobacco, and drug use behavior was found to differ by ethnocultural group. Further, each ethnocultural group was found to differ from the national average. The amount of difference between the national average and each ethnocultural group was related to the period of arrival and the length of time that an ethnocultural group has been present in Canada. The degree of similarity or difference between each ethnocultural group and the mainstream national average for alcohol, tobacco, and drug use and drug-use behavior may be used to measure the degree of social integration of each ethnocultural group and the degree of acculturation of women of specific ethnocultural groups into mainstream Canadian society.

Community-based facilities may be replacing hospitals for the treatment of alcoholism: the evidence from Ontario

We examined hospital utilization and use of community facilities for the treatment of alcohol problems in Ontario using Statistics Canada, Hospital Medical Records Institute records, and other administrative records. Between 1974 and 1986 there was a large drop in utilization of hospital services for treatment of alcohol problems. Rates of alcohol inpatient cases in general hospitals dropped by 47% and in mental hospitals by 33%. At the same time, there was an increase in overall availability of hospital beds and bed-days of care for all medical conditions, and no change in the total number of hospital discharges (1.3 million) and occupancy rates (80-85%). Also at the same time, the number of community-based programs for the treatment of alcohol problems increased, as did the number of persons or cases treated by them. This was associated with a drop of inpatient cases treated for alcohol problems in 38 out of 48 counties in Ontario (P < .0005). Multiple regression techniques were used to take into account the effect of the slight decline in overall alcohol consumption in this period. We found that after controlling for changes in alcohol consumption, the addition of one community-based alcohol treatment program was associated with a reduction in the number of cases treated on a hospital inpatient basis for alcohol-related problems, with a short-run drop of 27.1 hospital cases within 1 year of a community facility's availability and a long-run reduction of 52.2 cases. (P < .005).

Can life expectancies be used to determine if health promotion works?

PURPOSE

The goal of this study was to develop a method to measure the impact and cost-effectiveness of health promotion.

DESIGN

Age- and sex-specific changes in life expectancy in Canada between 1970 to 1972 and 1985 to 1987, after the introduction of national health insurance (1970) and health promotion (1975), are used to assess the impact due to biological hardiness, improvements in the health care field, and the effects of health promotion.

SUBJECTS

The subjects were the total male and female population of Canada between the years 1970 to 1972 and 1985 to 1987.

MEASURES

Life expectancy by years of age by sex was the measurement used.

RESULTS

A method is presented that allows the calculation of the differential effects of health promotion, health care, and biological hardiness on changes in life expectancy based on sequential subtraction of life expectancies for one-year age cohorts over a 15-year period. Results were obtained for each year of age for men and women, showing gender and age differences in the relative impact of the three factors. In this illustrative example using Canadian data, health promotion was found to have less impact on longevity than health care or biological hardiness. However, of the three, health promotion was the most cost-effective.

CONCLUSION

This method can be used to quantify changes in life span due to health promotion, health care, and biological hardiness for men and women at each year of age and to relate this to health expenditures for the whole population. The method is limited in that it cannot determine the relative impact of other factors that can affect life expectancy such as environmental changes or social trends.

Structure of intracellular mature vaccinia virus observed by cryoelectron microscopy

Intracellular mature vaccinia virus, also called intracellular naked virus, and its core envelope have been observed in their native, unfixed, unstained, hydrated states by cryoelectron microscopy of vitrified samples. The virion appears as a smooth rounded rectangle of ca. 350 by 270 nm. The core seems homogeneous and is surrounded by a 30-nm-thick surface domain delimited by membranes. We show that surface tubules and most likely also the characteristic dumbbell-shaped core with the lateral bodies which are generally observed in negatively stained or conventionally embedded samples are preparation artifacts.

Solution structure and direct imaging of fibronectin adsorption to solid surfaces by scanning force microscopy and cryo-electron microscopy

In this study, we present the scanning force and electron microscopic visualization of single molecules of fibronectin either frozen hydrated or adsorbed onto metallic and polymeric surfaces with different solid surface tensions. The surfaces were characterized by dynamic contact angle measurements, X-ray photo emission spectroscopy (XPS or ESCA) and scanning force microscopy. The proteins were prepared by fast protein liquid chromatography (FPLC) and characterized by gel electrophoresis. Protein films on surfaces were investigated by surface plasmon resonance spectroscopy and directly imaged by scanning force microscopy. The spreading of the adsorbed fibronectin revealed dependence on the chemical composition and the solid surface tension. Structure of fibronectin in solution as well as on solid interface appeared as an extended straight strand as obtained by imaging with electron and scanning probe microscopies. Imaging of DNA was performed by scanning force microscopy to test the accuracy and reproducibility of our measurements. The measured contour lengths were accurate and the larger widths were caused by convolution of the tip shape and sample. Frictional forces during the scan have been of significant contribution in the imaging mechanism. Moreover, this work demonstrated that scanning force microscopy can be used for mapping the orientation and organization of protein film adsorbed onto various surfaces at the nanoscale.

Effect of ethidium on the morphology, antiviral activity and subcellular distribution of poly r(A-U)

When ethidium bromide (EB) is combined with poly r(A-U) at an EB/ribonucleotide ratio of 1/4, the antiviral activity of the EB increases 22-fold. The increased antiviral activity is not due to increased interferon induction, direct viral inactivation or host cell cytotoxicity. Phase contrast, confocal and fluorescence microscopic observations reveal an increase in the nucleolar accumulation of the EB and/or the poly r(A-U) in the EB/poly r(A-U)-treated fibroblasts. Ultrastructure of negatively stained and replica preparations demonstrated that EB-induced condensation of poly r(A-U). These results suggest the elevated antiviral activity may be related to the altered uptake and subcellular distribution of the EB/poly r(A-U) complex.

Organization of turnip yellow mosaic virus investigated by neutron small angle scattering at 80 K: an intermediate state preceding decapsidation of the virion?

The organization of turnip yellow mosaic virus has been investigated by neutron small angle scattering at 300 K and 80 K in buffers containing various amounts of D2O. We confirm that in native virions, no substantial part of the RNA is located at a radius larger than ca. 100-110 A, i.e., that there is very little interpretation of the RNA into the capsid. At 80 K, scattering curves do not depend much upon contrast, from 40% D2O to 100% D2O buffers, but are strongly affected by interparticle interference. We could, however, show that it is not the case for the subsidiary intensity maximum at q approximately 0.06 A-1. From the position of this maximum, we conclude that upon freezing, the radius of the capsid expands by c.a. 3.5% and the RNA penetrates deeply into the protein shell. Biological implications of this conformational change immediately preceding decapsidation are discussed.

Atomic force microscopy of DNA in aqueous solutions

DNA on mica can be imaged in the atomic force microscope (AFM) in water or in some buffers if the sample has first been dehydrated thoroughly with propanol or by baking in vacuum and if the sample is imaged with a tip that has been deposited in the scanning electron microscope (SEM). Without adequate dehydration or with an unmodified tip, the DNA is scraped off the substrate by AFM-imaging in aqueous solutions. The measured heights and widths of DNA are larger in aqueous solutions than in propanol. The measured lengths of DNA molecules are the same in propanol and in aqueous solutions and correspond to the base spacing for B-DNA, the hydrated form of DNA; when the DNA is again imaged in propanol after buffer, however, it shortens to the length expected for dehydrated A-DNA. Other results include the imaging of E. coli RNA polymerase bound to DNA in a propanol-water mixture and the observation that washing samples in the AFM is an effective way of disaggregating salt-DNA complexes. The ability to image DNA in aqueous solutions has potential applications for observing processes involving DNA in the AFM.

In vitro decapsidation of turnip yellow mosaic virus investigated by cryo-electron microscopy: a model for the decapsidation of a small isometric virus

The in vitro decapsidation of a small isometric plant virus, turnip yellow mosaic virus (TYMV), was investigated by cryo-electron microscopy. Cryo-electron micrographs of TYMV and empty shells show that rapidly frozen virions still contain their RNA. Images of vitrified virions resemble closely those previously obtained by negative staining. Rapidly frozen virions decapsidate upon thawing although they remain well dispersed on the grid. The escape of the RNA through a hole at the periphery of the capsid could be visualized. The results suggest a model for the in situ decapsidation of small icosahedral viruses.