Phenolic compounds in blackcurrant (Ribes nigrum L.) leaves relative to leaf position and harvest date

Blackcurrant leaves are an essential source of phenolic compounds and this study investigated their variation relative to leaf positions and harvest date. The phenolic content varied between harvest dates, although leaf position on the shoot and interactions also played an important role. The contents of quercetin-malonyl-glucoside, kaempferol-malonyl-glucoside isomer and kaempferol-malonyl-glucoside were higher than that of the other identified phenolic compounds, whereas epigallocatechin was the lowest for all investigated leaf positions and harvest dates. The content of several of the compounds was highest in June, while quercetin-glucoside, kaempferol-glucoside and total phenols, increased towards the end of the season. Leaf position influenced the content of myricetin-malonyl-glucoside, myricetin-malonyl-glucoside isomer, quercetin-malonyl-glucoside and kaempferol-glucoside at the end of the season. Knowledge relating to the influence of ontogenetic and harvest time on the content of specific phenolic compounds might contribute in tailoring functional foods or pharmaceutical products using blackcurrant leaves as natural ingredients.

Tracking (Poly)phenol components from raspberries in ileal fluid

The (poly)phenols in ileal fluid after ingestion of raspberries were analyzed by targeted and nontargeted LC-MS(n) approaches. Targeted approaches identified major anthocyanin and ellagitannin components at varying recoveries and with considerable interindividual variation. Nontargeted LC-MS(n) analysis using an orbitrap mass spectrometer gave exact mass MS data which were sifted using a software program to select peaks that changed significantly after supplementation. This method confirmed the recovery of the targeted components but also identified novel raspberry-specific metabolites. Some components (including ellagitannin and previously unidentified proanthocyanidin derivatives) may have arisen from raspberry seeds that survived intact in ileal samples. Other components include potential breakdown products of anthocyanins, unidentified components, and phenolic metabolites formed either in the gut epithelia or after absorption into the circulatory system and efflux back into the gut lumen. The possible physiological roles of the ileal metabolites in the large bowel are discussed.

Compositional and toxicological analysis of a GM potato line with reduced α-solanine content--a 90-day feeding study in the Syrian Golden hamster

Steroidal glycoalkaloids (GAs) are toxins, produced by plants of the Solanaceae family. The potato plant (Solanum tuberosum L.) and its tubers predominantly contain the two GAs α-chaconine and α-solanine. These compounds are believed to act in synergy, and the degree of toxicity may therefore depend on their ratio in the potato. To determine the influence of α-solanine: α-chaconine ratio in potatoes on toxicity, a GM potato line (SGT 9-2) with reduced α-solanine content, and the parental control line (Desirée wild-type) having a traditional α-solanine: α-chaconine ratio were (1) studied for compositional similarity by analysing for a range of potato constituents, and (2) used in a 90-day feeding trial with the Syrian Golden hamster to study differential toxicity. The animal feeding study used diets with up to 60% freeze-dried potato powder from either line. Whilst data indicated some compositional differences between the GM line and its wildtype control these did not raise concerns related to nutritional value or safety. Results of the feeding trials showed a low number of significant differences between potato lines with different α-solanine: α-chaconine ratio but none were considered to raise safety concerns with regard to human (or animal) consumption.

Metabolomics and food processing: from semolina to pasta

The objective of this study was to investigate the metabolite variations during industrial pasta processing (from semolina to dried pasta) for five different commercial products. Up to 76 metabolites were detected. Significant differences were observed between wholemeal and refined pasta samples, with the wholemeal pasta richer in many classes of compounds such as phytosterols, policosanols, unsaturated fatty acids, amino acids, carotenoids, minerals, and so on. Significant differences were also observed between samples of refined pasta apparently similar for the actual parameters used for the assessment of pasta quality. The results indicated that a number of metabolites undergo a transformation during the pasta-making process depending on the processing conditions adopted. The approach used in this work shows the high potential of metabolite profiling for food investigations with regard to process-related transformation, safety, and nutrition.

Phytochemical diversity in tubers of potato cultivars and landraces using a GC-MS metabolomics approach

Phytochemical diversity with respect to a range of polar (including amino acids, organic acids, sugars, and sugar alcohols) and nonpolar (including fatty acids, alkanols, and sterols) metabolites was examined within tubers from a total of 29 genetically diverse potato cultivars and Chilean landraces using a metabolomics approach by gas chromatography-mass spectrometry. From principal component analysis of the polar and nonpolar metabolite data there was insufficient variation to differentiate the majority of cultivars and landraces. Analysis of all polar metabolite profiles revealed separation of two cultivars (Glenna and Morag) from the other cultivars and landraces and a separate cluster of one landrace line, largely due to higher levels of sugars. Pentland Javelin was distinct in containing high levels of many amino acids. The two Solanum tuberosum group phureja cultivars (Inca Sun and Mayan Gold) were not particularly similar and were not separated from the S. tuberosum group tuberosum cultivars. Analysis of the nonpolar metabolite data revealed partial separation of two landrace lines and, on the basis of some minor fatty acids, Mayan Gold was distinct. The differences in metabolite profiles are considered in terms of the taxonomy and breeding history of the cultivars and possible influences from other factors such as developmental stage of the tuber. With a view to exploring biosynthetic links between metabolites, a pairwise correlation analysis was performed on all metabolites. The significance of high correlations between many amino acids and between several nonpolar metabolites is discussed.

Acute toxicity of high doses of the glycoalkaloids, alpha-solanine and alpha-chaconine, in the Syrian Golden hamster

Sprouted, stressed, or spoiled potato tubers have reportedly led to human acute intoxication, coma, and death when consumed in high amounts. These effects have been attributed to glycoalkaloids (GAs), primarily alpha-solanine and alpha-chaconine, naturally present in all potatoes. The level of GAs in potato tubers has previously been shown to increase substantially as a result of improper handling and postharvest storage. A short-term study was performed to investigate the dose-response profile of alpha-solanine and alpha-chaconine alone or in combination, administered daily by oral gavage to Syrian Golden hamsters. Daily doses of 100 mg of alpha-solanine [kg body weight (BW)] (-1) induced death in two of four hamsters within 4 days, when administered by gavage to female Syrian hamsters. Doses of 100 mg of alpha-chaconine alone or alpha-solanine and alpha-chaconine combined in a ratio of 1:2.5, in doses of 75 or 100 mg (kg BW) (-1), induced death in one of four hamsters within the same period. Animals dosed with alpha-solanine alone or in combination with alpha-chaconine suffered from fluid-filled and dilated small intestines. The GA administration had no effect on acetyl cholinesterase (AChE) or butyryl cholinesterase (BuChE) activity in plasma or brain. Liquid chromatography-mass spectrometry-based metabolomics showed that there was a specific accumulation of alpha-chaconine in the liver tissues. In addition, metabolomics gave direct evidence of glycolytic metabolism of the GA with the beta 1, beta 2, and gamma-GAs detected in the urine and, to a lesser extent, the feces. Doses from 75 mg (kg BW) (-1) of alpha-chaconine, alpha-solanine, or the two compounds combined were potentially lethal within 4-5 days in the Syrian Golden hamster. However, the cause of death in these studies could not be established. No synergistic effects of alpha-solanine combined with alpha-chaconine were evident.

Synaptotagmin I is involved in the regulation of cortical granule exocytosis in the sea urchin

Cortical granules are stimulus-dependent secretory vesicles found in the egg cortex of most vertebrates and many invertebrates. Upon fertilization, an increase in intracellular calcium levels triggers cortical granules to exocytose enzymes and structural proteins that permanently modify the extracellular surface of the egg to prevent polyspermy. Synaptotagmin is postulated to be a calcium sensor important for stimulus-dependent secretion and to test this hypothesis for cortical granule exocytosis, we identified the ortholog in two sea urchin species that is present selectively on cortical granules. Characterization by RT-PCR, in-situ RNA hybridization, Western blot and immunolocalization shows that synaptotagmin I is expressed in a manner consistent with it having a role during cortical granule secretion. We specifically tested synaptotagmin function during cortical granule exocytosis using a microinjected antibody raised against the entire cytoplasmic domain of sea urchin synaptotagmin I. The results show that synaptotagmin I is essential for normal cortical granule dynamics at fertilization in the sea urchin egg. Identification of this same protein in other developmental stages also shown here will be important for interpreting stimulus-dependent secretory events for signaling throughout embryogenesis.

The biology of cortical granules

An egg-that took weeks to months to make in the adult-can be extraordinarily transformed within minutes during its fertilization. This review will focus on the molecular biology of the specialized secretory vesicles of fertilization, the cortical granules. We will discuss their role in the fertilization process, their contents, how they are made, and the molecular mechanisms that regulate their secretion at fertilization. This population of secretory vesicles has inherent interest for our understanding of the fertilization process. In addition, they have import because they enhance our understanding of the basic processes of secretory vesicle construction and regulation, since oocytes across species utilize this vesicle type. Here, we examine diverse animals in a comparative approach to help us understand how these vesicles function throughout phylogeny and to establish conserved themes of function.

SFE1, a constituent of the fertilization envelope in the sea urchin is made by oocytes and contains low-density lipoprotein-receptor-like repeats

At fertilization in most animals, cortical granules of the egg or oocyte secrete their contents, whose function it is to modify the extracellular matrix. This modified matrix then participates in the block to polyspermy and protection for early embryonic development. In the sea urchin, contents of the cortical granules are secreted within 30 sec of insemination. Several of these content proteins then bind to the nascent vitelline layer of the egg and lift off the cell surface to form a stable, impervious, fertilization envelope. At least six major proteins are present in the envelope, and recently we have identified cDNA clones of two, ovoperoxidase, and SFE9. Here we report on the identification and characterization of SFE1, a constituent of the fertilization envelope of the sea urchin Strongylocentrotus purpuratus, that has revealing characteristics of how the envelope might form and what protein interaction domains might predominate. We present the largest cDNA sequence we were able to identify representing approximately two thirds of the predicted protein coding region. The C-terminal half of the cognate SFE1 protein contains two different amino acid repeat motifs: a cysteine-rich (15%) motif of 40 amino acids that is tandemly repeated 22 times and is followed by a serine/threonine-rich (38%) repeat of 63 amino acids that is tandemly repeated 3.5 times. Surprisingly, just N-terminal to the cysteine-rich repeat region is a sequence of five repeats with similarity to repeats in another cortical granule protein, SFE9, and to the motif originally identified in the receptor of low-density lipoproteins, the LDLr motif. The amino acid composition deduced from the partial SFE1 cDNA is similar also to the composition of proteoliaisin, a protein thought to tether the ovoperoxidase to the vitelline layer of the egg and thereby sequester the crosslinking activity of the ovoperoxidase to a limited population of proteins in the fertilization envelope. However, by use of monoclonal and polyclonal antibodies to SFE1 and proteoliaisin, we show here that they are distinct gene products. We also show that SFE1 is packed selectively into the cortical granules and then is crosslinked into the fertilization envelope following fertilization. In situ RNA hybridization analysis shows that the mRNA of SFE1 (9 kilobases) is present in oocytes selectively and is turned over rapidly in the oocyte following germinal vesicle breakdown. Our findings suggest that the gene encoding this major product of the egg is activated concomitantly with the other cortical granule-specific products already identified, and that a common LDLr-like motif of the fertilization envelope may reveal a structural mechanism for protein interactions in its construction.

rab3 mediates cortical granule exocytosis in the sea urchin egg

Egg activation at fertilization in the sea urchin results in the exocytosis of approximately 15,000 cortical granules that are docked at the plasma membrane. Previously, we reported that several integral membrane proteins modeled in the SNARE hypothesis, synaptotagmin, VAMP, and syntaxin, in addition to a small GTPase of the ras superfamily, rab3, were present on cortical granules (Conner, S., Leaf, D., and Wessel, G., Mol. Reprod. Dev. 48, 1-13, 1997). Here we report that rab3 is associated with cortical granules throughout oogenesis, during cortical granule translocation, and while docked at the egg plasma membrane. Following cortical granule exocytosis, however, rab3 reassociates with a different population of vesicles, at least some of which are of endocytic origin. Because of its selective association with cortical granules in eggs and oocytes, we hypothesize that rab3 functions in cortical granule exocytosis. To test this hypothesis, we used a strategy of interfering with rab3 function by peptide competition with its effector domain, a conserved region within specific rab types. We first identified the effector domain sequence in Lytechinus variegatus eggs and find the sequence 94% identical to the effector domain of rab3 in Stronglocentrotus purpuratus. Then, with synthetic peptides to different regions of the rab3 protein, we find that cortical granule exocytosis is inhibited in eggs injected with effector domain peptides, but not with peptides from the hypervariable region or with a scrambled effector peptide. Additionally, effector-peptide-injected eggs injected with IP3 are blocked in their ability to exocytose cortical granules, suggesting that the inhibition is directly on the membrane fusion event and not the result of interference with the signal transduction mechanism leading to calcium release. We interpret these results to mean that rab3 functions in the regulation of cortical granule exocytosis following vesicle docking.

Members of the SNARE hypothesis are associated with cortical granule exocytosis in the sea urchin egg

Cortical granule exocytosis is important for the block to polyspermy at fertilization in the eggs of most vertebrates and many invertebrates. Cortical granules are poised at the cell surface and exocytose in response to sperm stimulation. Following exocytosis, the cortical granule contents modify the extracellular environment of the egg, the major result of which is to block additional sperm binding. Here we show that proteins homologous to members of the SNARE hypothesis-a molecular model designed to explain the trafficking, docking, and exocytosis of vesicles in the secretory compartment-are present in eggs at the right time and place to be involved in the regulation of cortical granule exocytosis. Using polymerase chain reaction (PCR) screens we have found homologues of synaptobrevin/VAMP, syntaxin, synaptotagmin, and rab3. Antibodies generated to fusion proteins or to synthetic peptides encoded by the cloned cDNAs were used in an immunofluorescence assay to show that each of the cognate proteins are present in the cortex of the egg. A synaptobrevin/VAMP homologue appears to be specifically associated with the membrane of cortical granules before fertilization and, following cortical granule exocytosis, is incorporated into the plasma membrane of the zygote. A rab3 homologue is also associated with cortical granules specifically but, following fertilization, the protein reassociates with different, yet undefined, vesicles throughout the cytoplasm of the zygote. Homologues of synaptotagmin and syntaxin are also present at the egg cortex but, in contrast to rab3 and VAMP, appear to be associated with the plasma membrane. Following fertilization, syntaxin and tagmin remain associated with the plasma membrane and are more readily immunolabeled, presumably due to an increased accessibility of the antibodies to the target protein domains. We also show by immunoblotting experiments that the cognate proteins are of the sizes predicted for these homologues. These results suggest that at least some steps in the biology of cortical granules may be mediated by SNARE homologues, and this finding, along with the unique biology of cortical granules, should facilitate examination of specific events of the fertilization reaction and the mechanism of stimulus-dependent exocytosis.

Flow cytometric study of differentiating cultures of Bacillus subtilis

We report on 1) the development of a flow cytometry-based technique for detecting beta-galactosidase in differentiating cultures of Bacillus subtilis and 2) the application of this technique in the study of early developmental gene expression. The problems associated with generating detectable signals (despite the small size of B. subtilis cells) have been overcome using the fluorogenic substrate 5-octanolyaminofluorescein di-beta-D-galactopyranoside (C8-FDG). Additionally, to control for background fluorescence during the staining process, we included a control population in the C8-FDG staining mixture that consists of cells devoid of the lacZ gene prestained with another dye, PKH26. The distinct emission spectra of C8-fluorescein and PKH26 allow nonspecific C8-FDG staining in this control population to be monitored using two-color analysis. This technique has been applied in the study of developmental gene expression in sporulating cultures of B. subtilis, and it has been found that such cultures are heterogeneous, comprising two cell populations. One population is induced for expression of early sporulation genes, which is determined using lacZ fusions, whereas the other remains uninduced. These results have allowed us to understand better the patterns of gene expression exhibited by wild-type and mutant cultures early during the development process of spore formation.

A quantitative study of electroporation showing a plateau in net molecular transport

Electroporation is believed to involve a temporary structural rearrangement of lipid bilayer membranes, which results in ion and molecular transport across the membrane. The results of a quantitative study of molecular transport due to electroporation caused by a single exponential pulse are presented; transport of four molecules of different physical characteristics across erythrocyte ghost membranes is examined as a function of applied field strength. Flow cytometry is used to quantitatively measure the number of molecules transported for 10(4) to 10(5) individual ghosts for each condition. This study has four major findings: 1) Net transport first increases with field strength, but reaches a plateau at higher field strengths. Significant transport is found at or below 1 kV/cm, and transport plateaus begin at field strengths between 2 and 5 kV/cm depending on the molecule transported. 2) A single population of ghosts generally exists, but exhibits a wide distribution in the amount of molecular transport. 3) Under the conditions used, the direction of transport across the ghost membrane does not appear to affect molecular transport significantly. 4) Large numbers of ghosts may be destroyed by the electroporation procedure.

Comparative clinical, microbiologic, and economic audit of the use of oral ciprofloxacin and parenteral antimicrobials

OBJECTIVE

To examine the use of oral ciprofloxacin and parenteral antimicrobials in the treatment of acute infection (respiratory tract, urinary tract, blood) in hospitalized patients, with particular reference to severity of infection, outcome, and associated economic implications of each treatment.

DESIGN

A prospective, multicenter comparative audit was conducted in the UK over an 18-month period. The audit was undertaken by clinical pharmacists who reviewed the antimicrobial treatment of patients with infective episodes, who were receiving or could have received oral therapy.

PARTICIPANTS

Clinical pharmacists who collated the data all are employed in teaching hospitals.

MAIN OUTCOME MEASURES

Patients were identified for analysis by their type of infection, severity of illness, antimicrobial prescribed, route of administration, and response to therapy. Additionally, data on costs of the antimicrobials prescribed and the supplementary costs of drug administration were calculated.

RESULTS

Four hundred eighty-five patients were enrolled for analysis; 208 of the patients had respiratory tract infection, 112 had urinary tract infection, 138 had septicemia, and 27 had mixed infections. Sepsis scores were applied to 152 patients receiving oral ciprofloxacin and 333 patients receiving parenteral antimicrobials and yielded mean scores of 5.9 (SD 3.1, range 1-13) and 8.7 (SD 4.2, range 1-22), respectively. Of 485 patients, 188 were paired according to sepsis score results and route of administration. Resolution occurred in 133 patients (79 receiving oral and 54 receiving parenteral therapy), further therapy was required in 49 (11 oral and 38 parenteral), and treatment was withdrawn in 6 (4 oral and 2 parenteral). Microbiologic assessment yielded positive results in 227 patients (47 percent). Drug acquisition costs (based on 1 UK pound = 1.80 US $) per course of treatment were $47.23 (SD $38.32, range 5.40-218.70) for the oral group and $173.70 (SD 209.77, range 2.11-1021.40) for the parenteral group. Overall costs for treatment courses were $74.00 (SD $52.81, range 8.10-309.17) and $305.59 (SD $304.70, range 14.69-1345.00) for the two groups, respectively (p < 0.001).

CONCLUSIONS

This study suggest that, in patients with moderate infective episodes, oral ciprofloxacin may reduce overall treatment costs compared with the use of parenteral antimicrobial agents.

Gene conversion between murine class II major histocompatibility complex loci. Functional and molecular evidence from the bm 12 mutant

The experiments presented in this study define the molecular basis of the bm 12 mutation. Initial characterization of an alloreactive T cell clone, 4.1.4, showed this clone to recognize an allodeterminant present on the E beta b and A beta bm12 chains, but not on the bm 12 parent A beta b chain. To define the extent of sequence shared between the I-E beta product and the mutant I-A beta product, we isolated a cDNA clone of the E beta b gene and determined its nucleotide sequence. Comparison of the nucleotide sequences of E beta b, A beta b, and A beta bm12 shows the the A beta bm12 gene to be identical to the E beta b gene in the region where it differs from its A beta b parent. We predict that the bm 12 mutation arose by gene conversion of this region, which spans 14 nucleotides between amino acid residues 67-71 of the mature A beta chain, from the E beta b locus to the corresponding position at the A beta b locus. Recognition of this region, which spans one of the previously defined E beta allelic "hypervariable" regions, by an alloreactive T cell clone provides the first direct evidence of the functional importance of these hypervariable regions in T cell stimulation. The identification of a gene conversion event involving one of these allelic variable regions implicates conversion as a mechanism that acts on class II beta genes to create sequence diversity in regions of Ia molecules that interact with foreign antigen or a T cell receptor, regions where protein sequence polymorphism would presumably be selected for by the expanded ability it affords the organism to mount effective immune responses against a wider variety of foreign antigens.

Successful evacuation of subdural hematoma in the presence of severe coagulopathy

An acute subdural hematoma was evacuated in the presence of a severe coagulopathy that was probably due to disseminated intravascular coagulation. A satisfactory result was achieved.

Spontaneous germinal matrix and intraventricular hemorrhage in prematurely born rabbits

Spontaneous hemorrhage into the ventricles in premature babies is a major problem, and neither its cause nor its pathogenesis is understood. A model is presented for the study of germinal matrix and intraventricular hemorrhage in the preterm rabbit. This animal is particularly suitable because, like the human, 1) the maximal growth of the brain occurs perinatally; 2) there is an abundant germinal matrix near term, and by birth this is substantially reduced; 3) there is no rete mirabile; 4) the blood flow to the brain is via the internal carotid and vertebral arteries; 5) the maturation of the lungs is completed just before term; and 6) the rabbit pup can maintain a separate existence from the dam when delivered prematurely. Eight of 64 such animals were found to have developed spontaneous germinal matrix hemorrhage with or without rupture into the ventricles. Several physiological and chemical features characteristic of the premature rabbit are presented. The hemorrhage in the lagomorph might be a paradigm of that in infants, and its study may aid in the understanding of the pathogenesis of the process.

Changes in the water and electrolyte pattern of the brain and of the intracranial pressure during development in rabbits

During its development the brain becomes dehydrated pari passu with growth and myelination and the electrolyte pattern changes from high sodium, low potassium to the opposite. The latter change is complete or virtually so in some species at term but in others the reversal is a postnatal occurrence. We have examined these features in rabbits of several ages and have measured the intracranial pressure at intervals during development as well. At or near both the water content of the brain is very high compared to that found later and the fetal electrolyte pattern is transitional in that the K/Na ratio is approximately one but not as high as in the mature brain. The intracranial pressure is lower in the newborn pups than it is later in development. Unlike that in mature animals the premature and young term rabbit brain is unable to affect ionic movements appropriate to the protection of the volume of the brain.

Thermal properties of cancellous bone

Specimens of beef bone were analyzed for thermal conductivity and thermal capacity. The thermal conductivity was about 7 X 10(-4) cal/cm/sec/degrees C, that is about the same as for other tissues. As regards thermal capacity, the determination of 0.73 cal/cm2/degrees C also was similar to that in other tissues. Both thermal conductivity and capacity were isotropic with respect to the layer of epiphyseal cartilage, and the orientation of bony trabeculae. Thermal probes were devised heated either by water or by electric current to destroy localized volumes of bone, as in surgery. To achieve necrotizing temperatures, the sizes of such probes and the times of application of heat were determined.