Harnessing water fleas for water reclamation: A nature-based tertiary wastewater treatment technology

Urbanisation, population growth, and climate change have put unprecedented pressure on water resources, leading to a global water crisis and the need for water reuse. However, water reuse is unsafe unless persistent chemical pollutants are removed from reclaimed water. State-of-the-art technologies for the reduction of persistent chemical pollutants in wastewater typically impose high operational and energy costs and potentially generate toxic by-products (e.g., bromate from ozonation). Nature-base solutions are preferred to these technologies for their lower environmental impact. However, so far, bio-based tertiary wastewater treatments have been inefficient for industrial-scale applications. Moreover, they often demand significant financial investment and large infrastructure, undermining sustainability objectives. Here, we present a scalable, low-cost, low-carbon, and retrofittable nature-inspired solution to remove persistent chemical pollutants (pharmaceutical, pesticides and industrial chemicals). We showed Daphnia's removal efficiency of individual chemicals and chemicals from wastewater at laboratory scale ranging between 50 % for PFOS and 90 % for diclofenac. We validated the removal efficiency of diclofenac at prototype scale, showing sustained performance over four weeks in outdoor seminatural conditions. A techno-commercial analysis on the Daphnia-based technology suggested several technical, commercial and sustainability advantages over established and emerging treatments at comparable removal efficiency, benchmarked on available data on individual chemicals. Further testing of the technology is underway in open flow environments holding real wastewater. The technology has the potential to improve the quality of wastewater effluent, meeting requirements to produce water appropriate for reuse in irrigation, industrial application, and household use. By preventing persistent chemicals from entering waterways, this technology has the potential to maximise the shift to clean growth, enabling water reuse, reducing resource depletion and preventing environmental pollution.

Stability of inflammation markers in human blood collected using volumetric absorptive microsampling (VAMS) under typical laboratory storage temperatures

Dried blood spots (DBS) collected on filter paper such as Guthrie cards are stored for years at room temperature. The assumption is that once dried, the samples remain stable and quantifiable indefinitely since the metabolites these were initially designed to measure, are known for their extended stability. The concentration of other blood proteins such as cytokines, however, are known to vary with storage even in liquid samples stored at -80 °C for extended periods of time. We sought to determine if cytokines are stable for up to 5 months when stored as a dried blood sample using volumetric absorptive microsampling (VAMS) devices. To test this, blood was collected from 4 healthy participants, spiked with recombinant cytokines, and collected into 30 µL VAMS devices. These prepared VAMS devices were stored at room temperature, 4 °C, or -20 °C for up to 5 months and matching VAMS liquid extracts were stored at -80 °C for the same period of time. At each timepoint, the samples were extracted from the VAMS devices and the extracts were analysed by Luminex® for quantification of up to 31 cytokines. These methods were also tested in a remote clinical study over a period of up to 8 months. Cytokine analysis revealed that room temperature, the current standard for DBS and VAMS storage, performed the poorest out of all storage temperatures with significant losses in 13/21 analytes compared to 4 °C at 5 months. Storage at 4 °C or colder performed well for the majority of analytes tested, however out of those, the optimal storage temperature differed for each analyte. There were a small number of analytes that performed poorly regardless of storage conditions and for fractalkine, this was found to be caused by inefficient recovery during extraction. Cytokine concentrations from finger-prick samples were also found to be much more variable that those in venous blood samples. Our results highlight the need to understand the stability of analytes of interest before committing to longitudinal collection and storage of samples in VAMS devices. These data give confidence that storage at 4 °C or colder was beneficial for cytokine stability. Wherein 25/31 cytokines were quantifiably stable at -20 °C when stored for 3 months and 17/21 were quantifiably stable after 5 months when stored at 4 °C.

Time-course proteome analysis reveals the dynamic response of Cryptococcus gattii cells to fluconazole

Cryptococcus gattii is an encapsulated fungus capable of causing fatal disease in immunocompetent humans and animals. As current antifungal therapies are few and limited in efficacy, and resistance is an emerging issue, the development of new treatment strategies is urgently required. The current study undertook a time-course analysis of the proteome of C. gattii during treatment with fluconazole (FLC), which is used widely in prophylactic and maintenance therapies. The aims were to analyze the overall cellular response to FLC, and to find fungal proteins involved in this response that might be useful targets in therapies that augment the antifungal activity of FLC. During FLC treatment, an increase in stress response, ATP synthesis and mitochondrial respiratory chain proteins, and a decrease in most ribosomal proteins was observed, suggesting that ATP-dependent efflux pumps had been initiated for survival and that the maintenance of ribosome synthesis was differentially expressed. Two proteins involved in fungal specific pathways were responsive to FLC. An integrative network analysis revealed co-ordinated processes involved in drug response, and highlighted hubs in the network representing essential proteins that are required for cell viability. This work demonstrates the dynamic cellular response of a typical susceptible isolate of C. gattii to FLC, and identified a number of proteins and pathways that could be targeted to augment the activity of FLC.

Sustained mitogen-activated protein kinase activation with Aggregatibacter actinomycetemcomitans causes inflammatory bone loss

Aggregatibacter actinomycetemcomitans is a gram-negative facultative capnophile involved in pathogenesis of aggressive forms of periodontal disease. In the present study, we interrogated the ability of A. actinomycetemcomitans to stimulate innate immune signaling and cytokine production and established that A. actinomycetemcomitans causes bone loss in a novel rat calvarial model. In vitro studies indicated that A. actinomycetemcomitans stimulated considerable production of soluble cytokines, tumor necrosis factor-α, interleukin-6 and interleukin-10 in both primary bone marrow-derived macrophages and NR8383 macrophages. Immunoblot analysis indicated that A. actinomycetemcomitans exhibits sustained activation of all major mitogen-activated protein kinase (MAPK) pathways, as well as the negative regulator of MAPK signaling, MAPK phosphatase-1 (MKP-1), for at least 8 h. In a rat calvarial model of inflammatory bone loss, high and low doses of formalin-fixed A. actinomycetemcomitans were microinjected into the supraperiosteal calvarial space for 1-2 weeks. Histological staining and micro-computed tomography of rat calvariae revealed a significant increase of inflammatory and fibroblast infiltrate and increased bone resorption as measured by total lacunar pit formation. From these data, we provide new evidence that fixed whole cell A. actinomycetemcomitans stimulation elicits a pro-inflammatory host response through sustained MAPK signaling, leading to enhanced bone resorption within the rat calvarial bone.

Difficult proteins

The degree of protein diversity and dynamic range within organisms means that even the simplest proteome cannot be captured by any single extraction and separation step. New techniques have focused on major protein classes often under-represented in proteome analysis; low abundance, membrane, and alkaline proteins. The last decade has seen considerable technology development in fractionation tools aimed at complexity reduction in many forms. The key outcome of complexity reduction is that each fraction, or sub-proteome, can be studied in more detail, and proteins which would have remained undetected in a total extract are present in sufficient quantities. However, the tools available are fractionations, not amplifications, and like all mining for rare and difficult items, a large amount of starting material is often required. The key shortcomings of many proteome analysis techniques are now well documented. With this knowledge, the best modern proteomics 'platform' involves combining multiple protein extractions, gel and chromatographic separations, and multiple MS analysis methods.

Accumulation parameters and seasonal trends for PCBs in temperate and boreal forest plant species

The concentration of polychlorinated biphenyls (PCBs) in the air and vegetation was measured periodically in two alpine forests, during the growing season. Foliage samples from nine plant species typical of the temperate and boreal environment were collected and analyzed. Leaf concentrations of tri- and tetra-CBs showed fast response times with changing temperature and gas-phase concentrations, suggesting that a partitioning equilibrium is approached relatively rapidly (few days) in the field. Heavier compounds showed kinetically limited accumulation trends, not reaching equilibrium during the growing season. Results were used to estimate the bioconcentration factors or equilibrium plant/air partition coefficient (KPA) for each species. Values of log KPA (calculated on a mass/volume basis) ranged between 0.78 and 1.96 and were correlated to the log KOA. Uptake trends of the higher chlorinated compounds showed intraspecific differences which were partially explained by the specific leaf area (SLA).

Expression of a cancer associated isoform of PCNA in breast cancer has implications as a potential biomarker

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Background: We have identified a novel cancer associated isoform of the protein, proliferating cell nuclear antigen (PCNA), termed (caPCNA), and demonstrated that this isoform arises through a direct protein post-translational modification, and not via genetic mutation or RNA splice variation. Our results suggest that caPCNA has the potential to serve as a highly effective and unique marker for identifying malignant breast cancer cells. Methods: This assertion is based on our proteomic-based analyses of more than 60 malignant and non- malignant breast cell lines and tissues. Commercially available antibodies against PCNA cannot distinguish between the different isoforms of PCNA present in malignant and non-malignant breast cells and cannot be used clinically to differentiate between normal and malignant breast tissue. However, we have recently developed a rabbit polyclonal antibody, (caPCNAab), which specifically recognizes only the caPCNA isoform expressed by malignant human breast cells. Results: Using this antibody we clearly show that caPCNA is expressed only in malignant breast cells and tissues, and can be found in early disease. caPCNA expression in tissues was quantified as average staining intensity X average percentage of cells stained. Using this criterion the following data were obtained: 10 cases of normal breast tissue (reduction mammoplasty) gave a total score of 1%; 35 cases of normal breast tissue adjacent to malignancy scored as 4%; 30 cases of DCIS scored as 90%; and 55 cases of invasive breast carcinoma scored as 120%. The five cases of ADH examined thus far were shown to score similar to that of normal breast tissue. Conclusions: The implication of these data is that the development of a caPCNAab-based IHC stain could potentially be used to reliably stain only in situ or invasive carcinoma, and distinguish genuinely benign lesions (e.g., ADH) from carcinoma, (e.g., DCIS) allowing definitive diagnosis in such cases where a limited amount of an atypical lesion prevents definitive diagnosis on routine H/E stained sections alone. For the patient population, this could result in a marked decrease in the need for either a repeat core biopsy or an excisional biopsy due to an inconclusive initial diagnosis.

No significant financial relationships to disclose.

How to Bring the “Unseen” Proteome to the Limelight via Electrophoretic Pre-Fractionation Techniques

The present review reports a panoply of electrophoretic methods as pre-fractionation tools in proteomic investigations in preparation for mass spectrometry or two-dimensional electrophoresis map analysis. Such electrophoretic pre-fractionation protocols include all those electrokinetic methodologies which are performed in free solution, most of them relying on isoelectric focusing steps (although some approaches based on gels and granulated media are also discussed). Devices associated with electrophoretic separations are multi-chamber apparatuses, such as the multi-compartment electrolyzers equipped with either isoelectric membranes or with isoelectric beads, Off-Gel electrophoresis in a multi-cup device and the Rotofor, an instrument also based on a multi-chamber system but exploiting the conventional technique of carrier-ampholyte-focusing. Other free-flow systems, as well as miniaturized chambers, are also described.

Fungal proteomics: mapping the mitochondrial proteins of a Trichoderma harzianum strain applied for biological control

Mitochondria are essential for cellular functions across organisms. A proteomic approach was taken to separate and identify mitochondrial proteins from a strain of Trichoderma harzianum with well established biocontrol properties. We optimized a method for the preparation of a sample enriched with mitochondria by ensuring efficient cell lysis and including several washing steps to minimize cytoplasmic contamination. We separated hundreds of proteins, using two-dimensional gel electrophoresis and identified 31 protein spots from T. harzianum, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and liquid chromatrography with mass spectrometry. Over 50% of the identified proteins were known to localize in the mitochondria. Three protein spots were identified from T. harzianum and a further five protein spots from the genera Trichoderma and Hypocrea. The remaining protein spots were identified by cross-species identification from other filamentous fungi, including Neurospora crassa and Aspergillus spp, and yeasts, including Saccharomyces cerevisiae and Schizosaccharomyces pombe. In total, we identified 25 protein spots from T. harzianum, representing proteins that have not been characterized in existing Trichoderma protein databases. To our knowledge, this is the first two-dimensional mitochondrial protein map of a filamentous fungus.

Prefractionation techniques in proteome analysis

The present review deals with a number of prefractionation protocols in preparation for two-dimensional map analysis, both in the fields of chromatography and in the field of electrophoresis. In the first case, Fountoulaki's groups has reported just about any chromatographic procedure useful as a prefractionation step, including affinity, ion-exchange, and reversed-phase resins. As a result of the various enrichment steps, several hundred new species, previously undetected in unfractionated samples, could be revealed for the first time. Electrophoretic prefractionation protocols include all those electrokinetic methodologies which are performed in free solution, essentially all relying on isoelectric focusing steps. The devices here reviewed include multichamber apparatus, such as the multicompartment electrolyzer with Immobiline membranes, Off-Gel electrophoresis in a multicup device and the Rotofor, an instrument also based on a multichamber system but exploiting the conventional technique of carrier-ampholyte-focusing. Other instruments of interest are the Octopus, a continuous-flow device for isoelectric focusing in a upward flowing liquid curtain, and the Gradiflow, where different pI cuts are obtained by a multistep passage through two compartments buffered at different pH values. It is felt that this panoply of methods could offer a strong step forward in "mining below the tip of the iceberg" for detecting the "unseen proteome".

Beta-elimination: an unexpected artefact in proteome analysis

Two persistent myths, ingrained in the electrophoretic literature of the last thirty years, namely carbamylation and deamidation, have been recently dispelled (Herbert et al., J. Proteome Res. 2002, in press). We report here, for the first time, a noxious and unexpected artefact in proteome analysis: beta-elimination (or desulfuration), which results on the loss of an H(2)S group (34 Da) from cysteine (Cys) residues for protein focusing in the alkaline pH region. With such an elimination event, a dehydro alanine residue is generated at the Cys site. In turn, the presence of a double bond in this position elicits lysis of the peptide bond, generating a number of peptides of fairly large size from an intact protein. The first process seems to be favored by the electric field, probably due to the continuous harvesting of the SH(-) anion produced. The only remedy found to this noxious degradation pathway is the reduction and alkylation of all Cys residues prior to their exposure to the electric field. Alkylation appears to substantially reduce both beta-elimination and the subsequent amido bond lysis.

Soft immobilized pH gradient gels in proteome analysis: a follow-up

As a follow-up of a previous work on two-dimensional map analysis utilizing soft (< 4%T) immobilized pH gradient (IPG) matrices in the first dimension (Candiano et al., Electrophoresis 2002, 23, 292-297), we have further optimized the preparation of such dilute IPG gels. One important step for obtaining an even reswelling of the entire IPG strip along the pH 3-10 interval is a washing step in 100 mM citric acid. It appears as though after rinsing off the excess acid in distilled water, a gradient of this tricarboxylic acid remains trapped into the IPG matrix, from almost nil at the acidic gel region to substantially higher amounts in its basic counterpart. This gradient helps in obtaining a uniform reswelling of the IPG strip, since carboxyl groups are more heavily hydrated than amino groups. The combined effects of uniform reswelling and of diluting the gel matrix favor penetration of large macromolecules (> 200 kDa) and allow for better spot resolution and for the display of a substantially higher number of spots also in the 30-60 000 Da region. A delipidation step in tri-n-butylphosphate:acetone:methanol (1:12:1) appears to substantially improve spot focusing and greatly diminish streaking and smearing of spots in all regions of the pH gradient.

Carbamylation of proteins in 2-D electrophoresis--myth or reality?

Carbamylation is widely quoted as being a problem in 2-D gel analysis and the associated sample preparation steps. This modification occurs when iso-cyanate, a urea break-down product, covalently modifies lysine residues, thus inducing a change in isoelectric point. Urea is used at up to 9 M concentrations in sample preparation and 2-D gels because of its ability to disrupt protein structure and effect denaturation without the need for ionic surfactants such as SDS. We have studied carbamylation using 7 M urea and 2 M thiourea, under a range of experimental temperatures to establish when, and if, it occurs and what can be done to minimize the modification. The actual time required for protein extraction from a tissue is usually short compared to the time required for procedures such as reduction and alkylation and IPG rehydration and focusing. Therefore, it is the temperature during these post-extraction procedures that is the most critical factor. Our experiments have shown that carbamylation does not occur during electrophoresis in the presence of urea, even with prolonged run-times. However, under poorly controlled sample preparation and storage conditions, it can become a major event.

Proteomics and immunomapping of reactive lymph-node and lymphoma

In the present study we show that two-dimensional (2-D) maps together with immuno-detection allow the precise identification of important leukocyte differentiation and tumor markers (e.g., CD3 and CD5), and important cell cycle regulatory molecules such as cyclin dependent kinases, notably CDK6. In addition, the comparative evaluation of molecular expression (e.g., CD5) in maps developed with normal and lymphoma samples can provide reproducible and precise information regarding the molecular expression in different cell populations. Accordingly, we could detect a much increased level of expression of CD5 in mantle cell lymphoma, up to ten times higher than in the control. In addition, CD5 in tumor tissues seems to be microheterogeneous as compared to normal samples.

Two-dimensional maps in soft immobilized pH gradient gels: a new approach to the proteome of the Third Millennium

Same major improvements in proteome analysis of cytosolic and membrane proteins by two-dimensional mapping are here reported. A much improved transfer of proteins from the first to the second dimensional sodium dodecyl sulfate (SDS)-gel is obtained by simply diluting the gel matrix, normally composed of 4%T polyacrylamide in all commercially available Immobiline strips down to as low as 3%T. In the analysis of total lysates of platelets, this augmented transfer has been evaluated as being 2-3 times higher than in standard 4%T gels. A second major improvement, in the case of analysis of membrane protein preparations, has been demonstrated to consist in a delipidation step in a tertiary solvent mixture composed of tri-n-butyl phosphate:acetone:methanol in a 1:12:1 ratio. By adopting this protocol, large amounts of spectrins (240-220 kDa, filamentous proteins of the red blood cell membranes) could be transferred vs. essentially none when delipidation was omitted. The present report also confirms the importance of a reduction and alkylation step of the protein sample prior to all electrophoretic steps, including focusing in the Immobiline gel, as recently reported by Herbert et al.

Proteomic analysis of a developmentally regulated secretory vesicle

Secretion of spore coat proteins from the prespore secretory vesicles (PSVs) in Dictyostelium discoideum is a signal mediated event that underlies terminal cell differentiation, and represents an important case of developmentally regulated secretion. In order to study the biochemical mechanisms that govern the regulated fusion of the PSVs with the plasma membrane and the subsequent secretion of their cargo, we purified this organelle from prespore cells. Analysis of protein extracts of highly purified PSVs indicated that, in addition to the cargo of structural spore coat proteins, many more proteins are associated with the PSVs. Their identification is paramount to the understanding of the mechanism of regulated secretion in this system. In this study we have taken the first comprehensive proteomic approach to the analysis of an entire, previously uncharacterized, organelle, with the goal of identifying the major proteins associated with the PSVs. We show that in addition to the structural spore coat proteins, the PSVs contain the enzymes needed for proper spore coat assembly (thioredoxin 2 and 3), regulatory proteins which we predict receive and transduce the developmental signal for secretion (rab7 GTPase, PI-3 kinase, NDP kinase and the calcium binding proteins calfumirin-1 and calreticulin) as well as proteins that interact with the cytoskeleton to mediate movement of the PSVs to the plasma membrane (actin binding proteins coactosin and profilin 1). In addition, the results suggest that proteins can play multiple roles in the cell, and that protein function can be dictated in part by subcellular localization. The identification of the PSV proteins is allowing us to develop testable hypotheses about the roles of these proteins within the functional context of developmentally regulated secretion.

Synthesis of 2-fluoro- and 6-fluoro-(2S,3R)-(3,4-dihydroxyphenyl)serine as potential in vivo precursors of fluorinated norepinephrines

The title compounds were prepared by the aldol condensation of 3,4-dibenzyloxy-2-fluorobenzaldehyde and 4,5-dibenzyloxy-2-fluorobenzaldehyde with the oxazolidinone 2, a chiral glycine equivalent. Removal of the chiral auxiliary and blocking groups produced the target amino acids 2-fluoro- and 6-fluoro-(2S,3R)-(3,4-dihydroxyphenyl)serine (1b and 1c) in >98% ee.

Reduction and alkylation of proteins in preparation of two-dimensional map analysis: why, when, and how?

The standard procedure adopted up to the present in proteome analysis calls for just reduction prior to the isoelectric focusing/immobilized pH gradient (IEF/IPG) step, followed by a second reduction/alkylation step in between the first and second dimension, in preparation for the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) step. This protocol is far from being optimal. It is here demonstrated, by matrix assisted laser desorption/ionization-time of flight (MALDI-TOF)-mass spectrometry, that failure to reduce and alkylate proteins prior to any electrophoretic step (including the first dimension) results in a large number of spurious spots in the alkaline pH region, due to "scrambled" disulfide bridges among like and unlike chains. This series of artefactual spots comprises not only dimers, but an impressive series of oligomers (up to nonamers) in the case of simple polypeptides such as the human alpha- and beta-globin chains, which possess only one (alpha-) or two (beta-) -SH groups. As a result, misplaced spots are to be found in the resulting two-dimensional (2-D) map, if performed with the wrong protocol. The number of such artefactual spots can be impressively large. In the case of analysis of complex samples, such as human plasma, it is additionally shown that failure to alkylate proteins results in a substantial loss of spots in the alkaline gel region, possibly due to the fact that these proteins, at their pI, regenerate their disulfide bridges with concomitant formation of macroaggregates which become entangled with and trapped within the polyacrylamide gel fibers. This strongly quenches their transfer in the subsequent SDS-PAGE step.

Protein alkylation in the presence/absence of thiourea in proteome analysis: a matrix assisted laser desorption/ionization-time of flight-mass spectrometry investigation

Although it is highly recommended that reduction and alkylation of free -SH groups in proteins should be performed prior to any electrophoretic step (including the first isoelectric focusing/immobilized pH gradient (IEF/IPG) dimension), it is here reported that one component of the sample solubilization cocktail adopted recently (namely thiourea) strongly quenches such alkylation process (as typically carried out with iodoacetamide, IAA). The present matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) analysis demonstrates that thiourea is an effective scavenger of IAA, since its sulfur atom reacts as efficiently as the ionized, free -SH group of Cys in proteins at alkaline pH values (pH 8.5-9.0). As a result of this reaction, free IAA is quickly depleted by thiourea, via the formation of an intermediate adduct, which is rapidly deamidated to form the cyclic compound thiazolinidone monoimine. This reaction strongly competes with the direct addition reaction of IAA onto the -SH group in proteins, resulting in poorly alkylated proteins. It is, therefore, recommended that, whenever possible and compatible with the type of sample, thiourea should be omitted from the solubilizing cocktail in proteome analysis. However, after proper sample reduction and alkylation, thiourea can be incorporated into the IEF/IPG gel, where it will have the beneficial effect of augmenting protein solubility at their pI values and scavenging the excess of free IAA.

Alkylation kinetics of proteins in preparation for two-dimensional maps: a matrix assisted laser desorption/ionization-mass spectrometry investigation

All existing protocols for protein separation by two-dimensional (2-D) gel electrophoresis require the full reduction, denaturation, and alkylation as a precondition for an efficient and meaningful separation of such proteins. Existing literature provides a strong evidence to suggest that full reduction and denaturation can be achieved in a relatively short time; the same thing, however, can not be said for the alkylation process, which the present study shows that more than 6 h are required for a complete alkylation. We have used matrix assisted laser desorption/ionisation-time of flight-mass spectrometry (MALDI-TOF-MS) to monitor protein alkylation by iodoacetamide over the period 0-24 h at pH 9. The present, fast and specific MS method provided clear indication on the extent and speed of alkylation which reached approximately 70% in the first 2 min, yet the remaining 30% resisted complete alkylation up to 6 h. The use of sodium dodecyl sulfate (SDS) during the alkylation step resulted in a strong quenching of this reaction, whereas 2% 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) exerted a much reduced inhibition. The implications of the present measurements on 2-D gel analysis in particular and proteomics in general are discussed.

The effect of protease inhibitors on the two-dimensional electrophoresis pattern of red blood cell membranes

The last few years have brought dramatic improvements for sample preparation and solubilization of protein for electrophoretic analyses. The use of reagents such as thiourea and novel sulfobetaine surfactants increases the total number of proteins able to be visualized from a complex mixture such as a cell lysate and also allows more hydrophobic membrane proteins to be resolved. As the red blood cell (RBC) contain no organelles, it is an ideal source of relatively pure plasma membrane for protein solubilization studies. In addition, there are a number of diseases related to abnormalities of RBCs proteins, thus it is of medical relevance as well as a test sample for technology development. However, the procedure for purifying RBC membranes is rather time-consuming and is normally carried out under almost physiological conditions, which can be conducive to proteolytic degradation of the membrane proteins. Significant differences in two-dimensional (2-D) patterns with and without protease inhibitors in sample preparation are demonstrated. In addition, is shown that preparation of RBC membranes with sodium carbonate, pH 11, leads to multimeric complexes of hemoglobin and causes hemoglobin to be irreversibly attached to the membrane. When using immobilized pH gradients (IPG) as the first dimension, it is demonstrated that the spectrins (large, filamentous proteins of 280 kDa) are lost from the 2-D map unless active, instead of passive, sample hydration into the IPG strip is adopted.

A turning point in proteome analysis: sample prefractionation via multicompartment electrolyzers with isoelectric membranes

Sample prefractionation, as obtained via multicompartment electrolyzers with isoelectric membranes, greatly enhanced the load ability, resolution and detection sensitivity of two-dimensional (2-D) maps in proteome analysis. This was demonstrated with different samples. In an Escherichia coli total cell extract, analysis by a 2-D map run in a pH 4-5 gradient showed many more spots when prefractionated, as compared with standard maps available in databases such as SWISS-2DPAGE. Analysis of human plasma in the pH 3-6 range showed an increase in the number of highly acidic proteins in the fractionated sample compared to whole plasma. With both samples no protein precipitation or smears occurred and much larger sample amounts could be loaded upon prefractionation, so that a large number of spots could be visualized by Coomassie staining, which is fully compatible with subsequent matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis.

Synthesis of (-)-7-epiaustraline and (-)-1-epicastanospermine

Highly efficient and selective syntheses of the title compounds are described. The cornerstone of the synthetic plan is the tandem inter [4 + 2]/inter [3 + 2] cycloaddition process. These syntheses differ from previous applications of this strategy in that they incorporate an alkylation in the hydrogenolysis step to close the second ring of the azabicyclic systems. Notable features of the sequence are (1) the highly regio- and stereoselective [3 + 2] cycloaddition of nitronate 15 with siloxymethyl (Z)-beta-silylvinyl ketone (Z)-22b and (2) the highly selective reduction of the resulting ketone 24a with L-Selectride. A single-crystal X-ray structure analysis of synthetic (-)-7-epiaustraline confirmed that the targeted structure was successfully synthesized. This stimulated a reexamination of the structural assignment of the natural product. (-)-1-Epicastanospermine was synthesized in four steps from the common intermediate 27a. The absolute configuration of (-)-1-epicastanospermine was assured by single-crystal X-ray structure analysis of intermediate (-)-27a. Thus, the sign of the optical rotation had to be revised. The overall efficiency of these syntheses were 9 steps and 23% yield for (-)-7-epiaustraline and 10 steps and 20% yield for (-)-1-epicastanospermine

Syntheses of (R)- and (S)-2- and 6-fluoronorepinephrine and (R)- and (S)-2- and 6-fluoroepinephrine: effect of stereochemistry on fluorine-induced adrenergic selectivities

Several routes to the enantiomers of fluoronorepinephrines (1) and fluoroepinephrines (2) were explored. A catalytic enantioselective oxazaborolidine reduction and a chiral (salen)Ti(IV) catalyzed asymmetric synthesis of silyl cyanohydrins proved efficacious in the key stereo-defining steps of two respective routes. Binding studies of the catecholamines with alpha(1)-, alpha(2)-, beta(1)-, and beta(2)-adrenergic receptors were examined. The assays confirmed that fluorine substitution had marked effects on the affinity of (R)-norepinephrine and (R)-epinephrine for adrenergic receptors, depending on the position of substitution. Thus, a fluoro substituent at the 2-position of (R)-norepinephrine and (R)-epinephrine reduced activity at both alpha(1)- and alpha(2)-receptors and enhanced activity at beta(1)- and beta(2)-receptors, while fluorination at the 6-position reduced activity at the beta(1)- and beta(2)-receptors. The effects of fluorine substitution on the S-isomers were less predictable.

Inhibition of human telomerase in immortal human cells leads to progressive telomere shortening and cell death

The correlation between telomerase activity and human tumors has led to the hypothesis that tumor growth requires reactivation of telomerase and that telomerase inhibitors represent a class of chemotherapeutic agents. Herein, we examine the effects of inhibition of telomerase inside human cells. Peptide nucleic acid and 2'-O-MeRNA oligomers inhibit telomerase, leading to progressive telomere shortening and causing immortal human breast epithelial cells to undergo apoptosis with increasing frequency until no cells remain. Telomere shortening is reversible: if inhibitor addition is terminated, telomeres regain their initial lengths. Our results validate telomerase as a target for the discovery of anticancer drugs and supply general insights into the properties that successful agents will require regardless of chemical type. Chemically similar oligonucleotides are in clinical trials and have well characterized pharmacokinetics, making the inhibitors we describe practical lead compounds for testing for an antitelomerase chemotherapeutic strategy.

Advances in protein solubilisation for two-dimensional electrophoresis

Two-dimensional (2-D) electrophoresis remains the highest resolution technique for protein separation and is the method of choice when complex samples need to be arrayed for characterisation, as in proteomics. However, in current proteome projects the total number of proteins identified from 2-D gels is often only a small percentage of the predicted proteome. In addition, there is an almost complete lack of hydrophobic proteins on 2-D gels, especially those using immobilised pH gradients. Recently there have been a number of publications reporting reagents which improve protein solubilisation prior to isoelectric focusing. The improved solubilization possible with these reagents has increased the total number of proteins able to be visualised on 2-D gels and also allowed the separation of hydrophobic proteins, such as integral membrane proteins.

Effect of nutrient limitation on adhesion characteristics of Pseudomonas aeruginosa

Pseudomonas aeruginosa causes a variety of diseases in humans including lung and ocular infections. Infections of the cornea are usually associated with wearing contact lenses and can result in loss of vision. This study aimed to determine the effect of carbon or nitrogen limitation on the adhesion to contact lenses of a strain of Ps. aeruginosa isolated from contact lens-related corneal inflammation. Cells were grown in a continuous culture apparatus in varying levels of glucose or ammonia to effect nutrient limitation. Adhesion to contact lenses was measured as total counts and viable counts. The cell surface hydrophobicity and charge were measured using adhesion to surface-modified Sepharose. Changes in lipopolysaccharide were determined using 1D SDS-PAGE and changes in cell-surface proteins were measured using 2D gel electrophoresis. The more the cultures were nitrogen limited, the greater the increase in adhesion to unworn hydrogel contact lenses 0.3 x 10(3) - 2.2 x 10(3) cells/mm2 on Etafilon A lenses. Cells that were carbon limited showed a greater increase in adhesion to contact lenses when the lenses had been coated in artificial tears. It appeared that lipopolysaccharide may have been involved in the constitutive adhesion to unworn lenses that occurred during C-limitation, whereas changes in the outer membrane proteins contributed to the increased adhesion under nitrogen limitation, or the change in adhesion that occurred to carbon-limited cells using contact lenses coated in artificial tears. Nine cell-surface proteins appeared during nitrogen limitation with kDa/pI of 75/4.8, 4.9, 5.0; 62/5.6; 89/6.5; 38/6.4; 28/1.5; 18/6.4; 12/4.5. Any or all of these may have been involved in the increased adhesion and further experiments are underway to examine this possibility.

Advances in protein solubilisation for two-dimensional electrophoresis

Two-dimensional (2-D) electrophoresis remains the highest resolution technique for protein separation and is the method of choice when complex samples need to be arrayed for characterisation, as in proteomics. However, in current proteome projects the total number of proteins identified from 2-D gels is often only a small percentage of the predicted proteome. In addition, there is an almost complete lack of hydrophobic proteins on 2-D gels, especially those using immobilised pH gradients. Recently there have been a number of publications reporting reagents which improve protein solubilisation prior to isoelectric focusing. The improved solubilization possible with these reagents has increased the total number of proteins able to be visualised on 2-D gels and also allowed the separation of hydrophobic proteins, such as integral membrane proteins.

Tandem Cycloaddition Chemistry of Nitroalkenes: Preparative and Theoretical Studies on the Stereochemical Course of [3 + 2] Cycloaddition of Cyclic Nitronates

Intermolecular [3 + 2] cycloadditions between two cyclic nitronates and a series of dipolarophiles are examined. High facial selectivity is observed in all cases and is analyzed with the aid of ab initio transition structure calculations. Monosubstituted dipolarophiles reacted with exclusive regiocontrol. Disubstituted dipolarophiles reacted with varying degrees of regiocontrol, which was dependent on the substituent. A theoretical approach for predicting regioselectivity is discussed. Exo selectivity was generally favored due to steric effects, and was especially high with cis-disubstituted dipolarophiles.

[Nutritional status of participants in the Giessen Senior Long-Term Study with respect to antioxidant vitamins and selenium]

Within the longitudinal study on nutrition and health status in an aging population of Giessen, Germany, baseline measurements with regard to antioxidant status were obtained in 85 free living elderly persons. The subjects were at least 60 years old, non-smoking, feeding themselves, and not supplementing any vitamins or minerals. Dietary intake of nutrients was assessed by means of a 3-day estimated food record, which was especially developed and validated for this study. Antioxidant status was evaluated by fasting plasma concentrations of vitamin C, E, beta-carotene, and selenium. The results show that in this study group self-determined nutrition provides enough nutrients to yield a good antioxidant status in the advanced age. Although no differences could be detected in dietary intake of vitamin C, E, and beta-carotene between males and females, significantly higher plasma concentrations of all substances investigated were found in females when compared to males.

Domestic violence and mental health: correlates and conundrums within and across cultures

Gender-based violence, only recently emerging as a pervasive global issue, contributes significantly to preventable morbidity and mortality for women across diverse cultures. Existing documentation suggests that profound physical and psychological sequelae are endemic following intimate partner violence. The presentation of domestic violence is often culture specific. A new lexicon, prompted by the expansion of human rights analysis, describes particular threats to local women including dowry deaths, honor murder, saiti, and disproportional exposure to HIV/AIDS as well as globally generic perils including abuse, battering, marital rape, and murder. While still fragmentary, accruing data reveal strengthening associations between domestic violence and mental health. Depression, stress-related syndromes, chemical dependency and substance (ab)use, and suicide are consequences observed in the context of violence in women's lives. Emerging social, legal, medical, and educational strategies, often culture specific, offer novel local models to promote social change beginning with raising the status of women. The ubiquity, gravity, and variability of domestic violence across cultures compel additional research to promote the recognition, intervention, and prevention of domestic violence that are both locally specific and internationally instructive.

Violence-related injuries in a pediatric emergency department

BACKGROUND

Since the 1980s, violence has emerged as a leading public health concern in the United States. Recent studies have begun to address the impact of interpersonal violence specifically on young children. The purpose of this study was to describe the epidemiology of violence-related injuries (VRI) in an urban pediatric emergency department (ED).

METHODS

A six-month retrospective chart review was conducted. The records of 11,000 patients 17 years of age and younger who were seen in an urban pediatric ED were accessed for VRI. VRI were defined as purposefully inflicted with intent to harm. Patients discharged from the ED with VRI were compared to patients admitted with VRI.

RESULTS

Three hundred seventeen (3%) of patients were categorized as having VRI during the six-month study period. Eighty-three percent were discharged, and 17% were admitted. The majority of injuries was the result of interpersonal conflict with a friend or acquaintance. Patients discharged were more likely to involve: younger children, female victims, and blunt instruments. Thirteen percent of discharged patients, however, involved potentially lethal weapons (knife or firearm).

CONCLUSIONS

The vast majority of patients with VRI are discharged from the ED. Females and young children were frequently evaluated for VRI in the pediatric ED. Identification of these patients can be used to initiate service protocols directed at violence prevention.

Ultrastructure and cytochemical detection of alkaline phosphatase in long-term cultures of osteoblast-like cells from rat calvaria

Two methods of collecting osteoblast-like cells from newborn rat calvaria were tested, either placing individual glass fragments or tipping dense glass beads onto the endocranial surface of periosteum-free bone. Inoculated at high density, cells collected by using these two methods form large mineralized plates after three weeks of culture. The main purpose of our investigation was to analyze the progressive formation of this mineralized structure and to localize alkaline phosphatase activity. At the beginning of the culture, flattened cells gathered into multilayers and synthesized collagen fibers. Cells in the upper layer became rapidly cuboidal in shape and continued to secrete collagen at their basal pole, whereas other cells became progressively embedded in the extracellular matrix. The upper cells featured ultrastructural characters of osteoblasts, whereas the embedded cells resembled osteocytes. After two weeks, the matrix began to mineralize: crystals appeared on collagen fibers, on matrix vesicles, and on cell debris. During the first days of the culture, the alkaline phosphatase activity was localized on the plasma membranes and on the collagen fibers. Thereafter, only the upper cells and collagen fibers that were juxtaposed to these cells showed alkaline phosphatase activity. In addition, the presence of mineralized matrix prevented the reaction product from being visualized on collagen fibers. The ultrastructural analysis reveals large mineralized plates with a structure resembling that of bone in vivo. This culture appears to be an appropriate model to study bone formation and regulation.

The HIV-infected house officer: residency training issues

Efforts to fully integrate physicians infected with the human immunodeficiency virus (HIV) into residency programs have been complicated by concerns of the potential risks of viral transmission from physician to patient. Despite numerous studies, this potential risk has not been quantified. This article addresses the issue of HIV-infected interns and residents, classifying HIV as a potential disability. The suggested recommendations emphasize routine monitoring and evaluation of professional competence and compliance with proper infection control procedures, as delineated by the Centers for Disease Control and Prevention. The need for hospitalwide guidelines and adequate health and disability insurance are also discussed.

Morphologic characterization of osteoblast-like cell cultures isolated from newborn rat calvaria

Two methods for harvesting osteoblast-like cell populations from newborn (10 days) rat calvaria were compared. The first one consisted in culturing the periosteum-free bones and then trypsinizing the cells on the bone surface. The second one involved the migration of the osteoblasts on glass fragments before trypsinization. Since the plating efficiency, the proportion of alkaline phosphatase-positive cells, the population doubling time, and the calcium deposition were more adequate, the second method was used to further characterize the behavior of the cultures. During the first week of culture, the cells featured shapes similar to those observed in vivo on the surface of periosteum-free calvaria. They formed multilayers and, in the presence of ascorbic acid, synthetized an organic matrix containing exclusively type I collagen. Later, small amounts of type III collagen appeared. The cells were embedded in the matrix and progressively acquired the morphologic phenotype of osteocyte-like cells. The matrix mineralized in the presence of beta-glycerophosphate. The technique of drop-inoculation (high concentration of cells in a small volume of medium) promoted the multilayer formation and the achievement of large mineralized plates (about 1 cm2) in 3 weeks of culture.