Production of enzymatic hydrolysates with in vitro antioxidant, antihypertensive, and antidiabetic properties from proteins derived from Arthrospira platensis

The microalga Arthrospira platensis BEA 005B was produced using 80 m² (9 m³) raceway photobioreactors achieving a biomass productivity of 28.2 g·m^-2·day^-1 when operating the reactors in semi-continuous mode (0.33 day^-1). The produced biomass was rich in proteins (58.1 g·100 g^-1) and carbohydrates (25.6 g·100 g^-1); the content of phycocyanins and allophycocyanins was 115.4 and 36.9 mg·g^-1, respectively. Ultrasounds and high-pressure homogenisation allowed recovering approximately 90% of the initial protein content of the biomass; however, the energetic requirements of the former (∼100 kJ·kg^-1) were significantly lower than those of high-pressure homogenisation (∼200 kJ·kg^-1). An in silico analysis revealed that papain and ficin would allow releasing a large number of bioactive peptides with antioxidant, antihypertensive (ACE-I and renin), and antidiabetic (DPP-IV, α-amylase, and α-glucosidase) properties. Both were assessed in vitro together with Alcalase and pepsin leading to the generation of enzymatic hydrolysates with in vitro bioactivity.

P-370 The vaginal microbiome in the first trimester of pregnancy is different in spontaneous versus IVF gestation

Study question

Are there differences in the vaginal microbiome of pregnant women who had a spontaneous pregnancy compared to those who required IVF?

Summary answer

The composition of the vaginal microbiome at 12 week's gestation is different in women who achieve the pregnancy spontaneously or by IVF.

What is known already

The vaginal microbiome plays an important role in women's reproductive health, finding associations between different microbiome patterns and the presence of infertility and embryo implantation failure in IVF. Additionally, recent studies show a correlation between obstetrics and perinatal outcomes and the composition of vaginal microbiota in pregnant women, as well as an increased risk of obstetrics complications in pregnant women after IVF.

Study design, size, duration

Observational, prospective and multicentre study. A total of 64 women were enrolled between January 2020 and June 2021. Spontaneous pregnancies n = 30; and IVF pregnancies n = 34.

Participants/materials, setting, methods

Vaginal swabs were obtained by speculum exam at 12 weeks of gestation in two public hospitals and a fertility private clinic in Spain, to evaluate the differences in vaginal microbiome between both cohorts. The microbiome composition was analyzed by sequencing the V3-V4 region of the 16S rRNA on the Illumina MiSeq platform.

Main results and the role of chance

There were no significant differences in socio-demographic characteristics between groups, except for an expected higher maternal age in the IVF cohort.

Lactobacillus was the most prevalent genus in both groups. When we compared the beta diversity of vaginal microbial by cohort a significant difference was obtained (p = 0.001).

Gardenella, Neisseria, Prevotella and Staphyloccocus were significantly enriched in the IVF group (p = 0.01).

A further evaluation of the four most abundant Lactobacillus species showed that Lactobacillus iners was dominant in IVF pregnancies (15.2%) compared to spontaneous (9.8%) (p = 0.002). On the other hand, Lactobacillus  gasseri showed a lower abundance in vaginal microbiome from women belonged to IVF (9.2%) vs spontaneous pregnant group (13.8%) (p = 0.005).

These findings allowed us to create a model to identify a microbial signature. This model is able to discriminate between IVF and spontaneous pregnancies.

Limitations, reasons for caution

The main limitation of our study is the small sample size. Larger studies are needed to corroborate our findings and their relationship with important aspects such as obstetric and perinatal complications.

Wider implications of the findings

The microbiome composition is different between both cohorts. The microbiome found in our IVF cohort has been also associated with obstetric complications as preterm delivery in previous studies. This suggest that the microbiome composition could be a plausible etiology for a higher risk of adverse pregnancy outcomes in IVF patients.

Trial registration number

Not applicable

Color of extra virgin olive oils enriched with carotenoids from microalgae: influence of ultraviolet exposure and heating

A carotenoid-rich extract containing 2.5 mg/mL of lutein and 3.3 mg/mL of β-carotene from the microalga Scenedesmus almeriensis was added to ten extra virgin olive oils from four Spanish cultivars with differing degrees of ripeness, obtaining carotenoid enriched oils with lutein and β-carotene concentrations of 0.082 and 0.11 mg/mL, respectively. Extra virgin olive oils enriched with carotenoids from microalgae were studied by analyzing the effect on color of three different treatments: ultraviolet exposure, microwave heating and immersion bath heating. The methodology was designed to simulate, in controlled laboratory conditions, the effects of household treatments. Spectrophotometric color measurements were then performed to monitor color changes in the enriched and non-enriched extra virgin olive oil samples. Enriched oils are much more chromatic, darker and redder than natural oils. After 55 days UV irradiation, 40 min microwave heating, and 72 hours thermostatic heating, the average color differences for natural/enriched extra virgin olive oils were 98/117, 15/9 and 57/28 CIELAB units, respectively. In general, increasing temperature and ultraviolet exposure produced higher CIELAB color differences in the non-enriched samples. The addition of microalga extracts to extra virgin olive oils was found to induce some color stability and may constitute a future way of increasing the daily intake of beneficial bioactive compounds such as carotenoids.

Identification of vaginal microbiome associated with IVF pregnancy

The factors that cause a preterm birth (PTB) are not completely understood up to date. Moreover, PTB is more common in pregnancies achieved by in-vitro fertilization (IVF) than in spontaneous pregnancies. Our aim was to compare the composition of vaginal microbiome at 12 weeks of gestation between women who conceived naturally or through IVF in order to study whether IVF PTB-risk could be related to vaginal microbiome composition. We performed an observational, prospective and multicentre study among two public hospitals and a fertility private clinic in Spain. Vaginal swabs from 64 pregnant women at 12 weeks of gestation were collected to analyse the microbiome composition by sequencing the V3-V4 region of the 16S rRNA. Our results showed that the vaginal microbiome signature at 12 weeks of pregnancy was different from women who conceived naturally or through IVF. The beta diversity and the genus composition were different between both cohorts. Gardnerella, Neisseria, Prevotella, and Staphylococcus genus were enriched genus in the vaginal microbiome from the IVF group, allowing us to create a balance model to predict both cohorts. Moreover, at species level the L. iners abundance was higher and L. gasseri was lower in the IVF group. As a conclusion, our findings were consistent with a proposed framework in which IVF pregnancy are related to risk for preterm birth (PTB) suggesting vaginal microbiome could be the reason to the relation between IVF pregnancy and risk for PTB.

The role of seagrass meadows in the coastal trapping of litter

The accelerated discard and mismanagement of human-made products are resulting in the continued input of litter into the oceans. Models and field observations show how floating litter can accumulate in remote areas throughout the global ocean, but far less is known about the non-floating litter fraction. Seagrass meadows play an important role in the sediment and natural-debris dynamics, and likely also in the storage and processing of non-floating litter. In this work, non-floating litter was studied across six Posidonia oceanica meadows. Litter accumulated mainly around the landside edge of the meadow. The outer margin of the edge predominantly trapped macro-litter, whilst microplastics accumulated mainly along the inner margin. On average, macro-litter concentrations increased 3-fold after heavy rainfall. Retention of non-floating litter by coastal meadows facilitates the recurrent landward-seaward conveyance of the easily-transportable litter (mainly plastic items) and its fragmentation before it is buried or transferred to deeper areas.

Distribution and abundance of microplastics in coastal sediments depends on grain size and distance from sources

Microplastic deposition in marine sediments is a geographically widespread problem. This study examines microplastics in intertidal and subtidal sediments at 87 locations in habitats designated as Special Areas of Conservation (SACs) and Special Protection Areas (SPAs) on the coastline of Ireland. Established methodological approaches including, organic matter digestion, density separation, particle extraction and polymer identification were applied. Microplastic abundance was closely related with distance from known sources and concentrations were greater in intertidal as opposed to subtidal sediments. Colourless, polyethylene fibres and polypropylene fragments were the most abundant MP recorded and finer grained sediments were shown to entrap more MPs than coarser sediments. The results demonstrate that an understanding of potential sources of pollution, sediment type and hydrodynamic conditions are very important in terms of MP abundance and distribution in marine sediments and also in terms of effective waste management strategies and policy aimed at reducing the global plastics problem.

Using a B-Phycoerythrin Extract as a Natural Colorant: Application in Milk-Based Products

Nowadays, there is a growing interest in finding new coloring molecules of natural origin that can increase and diversify the offer of natural food dyes already present in the market. In the present work, a B-phycoerythrin extract from the microalgae Porphyridium cruentum was tested as a food colorant in milk-based products. Using spectroscopy and colorimetry, the extract was characterized and gave evidence of good properties and good stability in the pH range between 4.0 and 9.0. Coloring studies were conducted to demonstrate that samples carrying the pink extract could be used for simulating the pink color of marketed milk-based products. The staining factors, representing the amount of pink protein to be added to reproduce the color of strawberry commercial products, ranged between 1.6 mg/L and 49.5 mg/L, being sufficiently low in all samples. Additionally, color stability during a short period of cold storage was studied: it demonstrated that the three tested types of dairy products remained stable throughout the 11-day analysis period with no significant changes. These results prove the potential of the B-phycoerythrin extract as a natural colorant and alternative ingredient to synthetic coloring molecules.

Strength limits in mesoscaled 3Y-TZP ceramics for micro-surgical instruments

Micro-surgical instruments are a new application for mesoscale ceramics formed using the lost mold-rapid infiltration forming (LM-RIF) process. Instrument strength and reliability are the foremost concerns for this sensitive application. It is hypothesized that increasing grain size can improve the damage tolerance of the parts associated with the transformation toughening in the 3Y-TZP material, while retaining high strength. In this work, mesoscale bend bars (314 × 22 × 18 µm) of 3Y-TZP fabricated using the LM-RIF process were heat treated at 1400 °C for 1 h, 8 h, or 16 h, respectively, to obtain samples with different grain sizes. Strength tests were performed under three-point bending and results were evaluated using Weibull statistics. Fractographic and confocal Raman spectroscopic analyses were carried out to interpret the data. Experimental findings showed that the characteristic strength decreased with increasing grain size contrary to the damage tolerance hypothesis. An Orowan-Petch model was recalled to correlate the strength with the flaw size to grain size ratio. At fine grain sizes the strength was controlled by the flaws introduced by the LM-RIF process, whereas at large grain sizes the strength become more grain size controlled. Although larger-grained samples did have a higher propensity to transform, and thus increase toughening, exaggerated grain growth in some of the specimens tested caused an additional flaw population which led to an overall lower strength. Finally, based on the experimental observations and fracture mechanics considerations, we believe that an upper bound of ∼2.5 GPa exists for the strength of mesoscale as-fabricated 3Y-TZP ceramic parts.

[Takotsubo cardiomyopathy in the context of Staphylococcus aureus sepsis]

Takotsubo cardiomyopathy consists of a transient dysfunction of the left ventricle. It is characterised by an impaired left ventricular segmentary contractility, without significant coronary lesions in the coronary angiography. It usually occurs after an episode of physical or emotional stress. We present the case of a 70 year-old woman, who, in the postoperative period of an ankle osteosynthesis, developed a Takotsubo cardiomyopathy in the context of a sepsis caused by Staphylococcus aureus. She presented with acute lung oedema and a clinical picture of low cardiac output. The echocardiogram showed left ventricular medioapical akinesia. Coronary angiography was normal. She was treated with supportive measures with good progress. At 33 days from onset she was able to be discharged from hospital to home with normal systolic function on echocardiography.

Whisking in air: encoding of kinematics by VPM neurons in awake rats

Rodent whisking behavior generates two types of neural signals: one produced by whisker contact with objects; the other by movements in air. While kinematic signals generated by contact reliably activate neurons at all levels of the trigeminal neuraxis, the extent to which the kinematics of whisking in air are reliably encoded at each level remains unclear. Previously, we showed that the responses of trigeminal ganglion (TG) neurons in awake, head-fixed rats are correlated with whisking kinematic parameters, but that individual neurons may differ substantially in the reliability of their kinematic encoding. Here, we extend that analysis to neurons in the ventral posterior medial (VPM) nucleus. Three possible coding strategies were examined: (1) firing rate across an entire movement; (2) the probability of individual spikes as a function of the instantaneous movement trajectory; and (3) the coherence between spikes and whisking. While VPM neurons were clearly responsive to variations in whisker kinematics during whisking in air, the encoding of whisker kinematics by VPM neurons was less consistent than that of TG neurons. Furthermore, we found that, in VPM as in TG, movement direction is an important determinant of unit responsiveness during whisking in air.

One whisker whisking: unit recording during conditioned whisking in rats

Understanding of the functional neurobiology of the rodent whisker system would be advanced by neurobehavioral studies in awake, behaving animals that combine unit recording from structures at various levels of the system with quantitative characterization of the kinematics and temporal organization of whisking. Such studies require the solution of a number of methodological problems. These include: chronic recording procedures ensuring unit isolation, stability and maximum yield, monitoring and display of unit activity and whisker movements within the same (ms) timeframe and behavioral paradigms which bring whisking movement parameters under the control of the experimenter rather than the rat. Here we describe a head-fixed rodent preparation which makes possible chronic recording of unit activity in the awake, whisking rat, combined with real-time, high resolution monitoring of whisker and pad movements in two dimensions and under behavioral control. While the head-fixed "whisking" preparation has some inherent limitations, it may be used to address a number of important neurobehavioral problems. We suggest that it should contribute significantly to understanding the functional neurobiology of the whisker system.

Topography of whisking II: Interaction of whisker and pad

The peripheral effector system mediating rodent whisking produces protraction/retraction movements of the whiskers and translation movements of the collagenous mystacial pad. To examine the interaction of these movements during whisking in air we used high-resolution, optoelectronic methods for two-dimensional monitoring of whisker and pad movements in head-fixed rats. Under these testing conditions (1) whisker movements on the same side of the face are synchronous and of similar amplitude; (2) pad movements exhibit the characteristic 'exploratory' rhythm (6-12 Hz) of whisking but their movements often have a low frequency (1-2 Hz) component; (3) Pad movements occur in both antero-posterior and dorso-ventral planes but there are considerable variations in the amplitude and topography of movement parameters in the two planes. We conclude that (a) both whisker and pad receive input from a common central rhythm generator; (b) differences in whisker and pad amplitude and topography probably reflect differences in the biomechanical properties of the structures receiving that input; (c) pad movements make a significant contribution to the kinematics of whisking behavior and (d) the two-dimensional nature of pad translation movements significantly increases the rat's flexible control of its mobile sensor.

Use of contraceptive methods and risk of unwanted pregnancy in Spanish women aged 40–50 years: results of a survey conducted in Spain

A survey intended to ascertain the rate of use and type of contraceptive methods applied by Spanish women aged 40 to 50 years, and to determine the proportion of women in this group at risk of an unwanted pregnancy, was designed and validated. To achieve representative national results for the study population, it was estimated that a sample size of 2000 women was required. Women were selected using probabilistic, stratified random sampling. The survey questionnaire was prepared by the research group with the collaboration of experts in the conduct of population studies of this type. Participants were interviewed face to face by qualified and trained staff from a specialised company external to the research group. Overall, 1039 women (52%) resorted to some contraceptive method, of which (male or female) sterilisation was the most common. We estimate that in Spain there are 840,000 women (31.8%) aged 40 to 50 years at risk of unwanted pregnancy.

Ambient air levels of volatile organic compounds (VOC) and nitrogen dioxide (NO2) in a medium size city in Northern Spain

Ambient concentrations of volatile organic compounds (VOC) and nitrogen dioxide (NO2) were measured by means of passive sampling at 40 sampling points in a medium-size city in Northern Spain, from June 2006 to June 2007. VOC and NO2 samplers were analysed by thermal desorption followed by gas chromatography/mass-selective detector and by visible spectrophotometry, respectively. Mean concentrations of benzene, toluene, ethylbenzene, xylenes, propylbenzene, trimethylbenzenes, and NO(2) were 2.84, 13.26, 2.15, 6.01, 0.59, 1.32 and 23.17 microg m(-3) respectively, and found to be highly correlated. Their spatial distribution showed high differences in small distances and pointed to traffic as the main emission source of these compounds. The lowest levels of VOC and NO2 occurred during summer, owing to the increase in solar radiation and to lower traffic densities. Mean concentrations of benzene and NO2 exceeded the European limits at some of the monitored points.

Whisking in air: encoding of kinematics by trigeminal ganglion neurons in awake rats

Active sensing requires the brain to distinguish signals produced by external inputs from those generated by the animal's own movements. Because the rodent whisker musculature lacks proprioceptors, we asked whether trigeminal ganglion neurons encode the kinematics of the rat's own whisker movements in air. By examining the role of kinematics, we have extended previous findings showing that many neurons that respond during such movements do not do so consistently. Nevertheless, the majority ( approximately 70%) of trigeminal ganglion neurons display significant correlations between firing rate and a kinematic parameter, and a subset, approximately 30%, represent kinematics with high reliability. Preferential firing to movement direction was observed but was strongly modulated by movement amplitude and speed. However, in contrast to the precise time-locking that occurs in response to active whisker contacts, whisker movements in air generate temporally dispersed responses that are not time-locked to the onset of either protractions or retractions.

Exposure to volatile organic compounds (VOC) in public buses of Pamplona, Northern Spain

This study examines the exposure level of passengers and drivers to VOC in public buses in a medium-size metropolitan area (Northern Spain). In-vehicle monitoring was performed on different routes, on peak and non-peak hours, during January and February 2007. A total of 112 air samples were collected onto adsorbent tubes and analysed by thermal desorption (TD) and gas chromatography/mass selective detector (GC/MSD) technique. Statistical differences were found among route to route concentrations, with those routes with major prevalence in the commercial area of the city displaying higher values; differences between peak and non-peak hours were also observed. A decrease in VOC concentrations was also registered during the weekend. BTEX ratios were estimated and found to be related to traffic emissions and similar for all the surveyed routes. Correlations confirmed traffic as the main emission source for BTEX and trimethylbenzene, their concentrations being highly associated to changes in meteorological conditions.

Development of a method for the determination of ibafloxacin in plasma by HPLC with flourescence detection and its application to a pharmacokinetic study

A simple, rapid, and sensitive high-performance liquid chromatographic method is developed for the determination of ibafloxacin in rabbit plasma. Plasma proteins are precipitated with acetonitrile, and after extraction with methylene chloride followed by desecation, ibafloxacin is determined by reversed-phase chromatography with fluorescence detection exciting at 330 nm and emission at 368 nm. Peaks corresponding to ibafloxacin and the internal standard (salycilic acid) are obtained at 9.8 and 5.2 min, respectively. The method is validated for a limit of quantitation of 10 ng/mL. The intraday relative standard deviation ranges from 4.78-7.15%, and the interday precision ranges from 1.32-4.03%. The method shows linearity for the two calibration curves used (10-100 ng/mL and 100-2000 ng/mL). The procedure described is applied successfully to a pharmacokinetics study of ibafloxacin in rabbits.

Contraceptive practices and trends in Spain: 1997-2003

OBJECTIVE

To know the contraceptive use and trends in the Spanish female population.

STUDY DESIGN

Since 1997, we have conducted a survey every 2 years on the use of contraceptive methods among a representative sample of Spanish women of childbearing potential (15-49 years).

RESULTS

In the period 1997-2003, the percentage of use of contraceptive methods in Spain rose from 55.6% to 71.2%. The most commonly used method was the condom (21% in 1997, 21.9% in 1999, 29.5% in 2001 and 35.7% in 2003), followed by the contraceptive pill (14.2%, 16.5%, 19.2% and 18.3%, respectively). Male or female sterilization remained stable with percentages of use of 5-7%. IUDs are used by about 5% of women.

CONCLUSIONS

The use of contraceptive methods among Spanish women of childbearing potential generally fits quite well the patterns found in other developed countries, and we observed a trend towards increased use of effective methods.

Contraception in the Spanish press: an analysis of the 1997-2002 period

OBJECTIVE

Based on the hypothesis that the media represent an important source of information about contraceptive methods and sexuality, this paper reviews the news items about contraception published by four important Spanish newspapers and four women's magazines.

MATERIALS AND METHODS

All news items appearing from January 1, 1997 to December 31, 2002 in the following publications: El País, El Mundo, ABC, La Vanguardia, Mía, Clara, Ragazza, and Epoca were collected during the first 6 months of 2003. Results Seven hundred and ten news items about contraception were identified during the period analysed, of which 117 (16.5%) had a negative character.

CONCLUSIONS

Over 80% of news items appearing in the Spanish press in the 1997-2002 period give a positive information about contraceptive methods.

Spatial and temporal trends of volatile organic compounds (VOC) in a rural area of northern Spain

Ambient concentrations of volatile organic compounds (VOCs) were measured at 40 rural sampling points in Navarre (northern Spain). Air samples were collected by means of sorbent passive sampling and analyzed by thermal desorption (TD) and gas chromatography/mass-selective detector (GC/MSD). A total of 140 VOCs were identified during the study, which was carried out between May to October 2004 for a total of a 10 biweekly sampling campaigns. Concentrations of benzene, toluene, ethylbenzene, m/p-xylenes, o-xylene (BTEX) and 1,3,5-trimethylbenzene were determined in order to investigate their temporal and spatial distributions. Geostatistical analysis pointed to traffic as the main emission source of these compounds. Supporting this idea, BTEX and nitrogen oxides concentrations were found to be highly significantly correlated (r = 0.495, P = 0.001), whereas a strong negative correlation between BTEX and ozone was also observed (r = -0.355, P = 0.025). The concentrations for the BTEX group were similar to the values that have been previously reported for other rural areas.

2‘,7‘-Difluorofluorescein Excited-State Proton Reactions: Correlation between Time-Resolved Emission and Steady-State Fluorescence Intensity

The presence of excited-state buffer-mediated proton exchange reactions influences the steady-state fluorescence signals from dyes in solution. Since biomolecules in general have some chemical groups that can act as proton acceptors/donors and are usually dissolved in buffer solutions which can also behave as appropriate proton acceptors/donors, the excited-state proton exchange reactions may result in distorted steady-state fluorescence signals. In a previous paper (J. Phys. Chem. A 2005, 109, 734-747), we evaluated kinetic and other pertinent parameters for the excited-state proton reactions of the prototropic forms of 2',7'-difluorofluorescein (Oregon Green 488, OG488), recording a fluorescence decay surface at different pH values and acetate buffer concentrations, analyzed by means of global compartmental analysis. In this article we use the rate constants and the corrected pre-exponential factors from the previously recorded fluorescence decay traces to simulate the decay times and associated pre-exponentials at different acetate buffer concentrations and constant pH and compare these theoretically calculated values with new experimental data. We also calculate the steady-state fluorescence intensity vs pH and vs acetate buffer concentration (at constant pH) and compare these calculated emission values with the experimental data previously published. The agreement between the experimental and simulated data is excellent.

Fluorescent behavior of B-phycoerythrin in microemulsions of aerosol OT/water/isooctane

Taking advantage of its unusual fluorescent properties, the incorporation of B-phycoerythrin (B-PE) in aerosol OT (AOT, sodium bis-(2-ethylhexyl) sulphosuccinate)/water/isooctane microemulsions was investigated by following their steady-state and time-resolved fluorescence as a function of the water-to-surfactant molar ratio, w(0). The fluorescent intensity at 575 nm increased continuously with increasing water content, saturating at a w(0) around 35 and staying practically constant at w(0)> or =40. The steady-state anisotropy showed an initial increase with increasing water content until w(0)=23 and then decreased strongly, staying practically constant when w(0)> or =40. The values of the fluorescent parameters, anisotropy and fluorescent intensity, were unchanged when the water content of the system increased in the range between w(0)=40 to 50. This implies the effective incorporation of B-PE in the microemulsion droplets with w(0)> or =40, as well as the equilibrium of the dispersion at these water/surfactant ratios, since higher water content does not affect the main surrounding microenvironment of the protein. The overall incorporation in the microemulsion droplets caused minor spectroscopic changes with respect to biliprotein in aqueous solution of 20 mM sodium phosphate buffer, pH 7.0, such as a blue absorption shift of 3 nm and an emission shift of 1.5 nm, as well as a slight increase in excitation anisotropy spectrum mainly caused by a decrease in protein mobility. Therefore, there are no important interactions between the chromophores and the AOT sulfonate head groups. Emission intensity decays followed complex kinetics in both aqueous and dispersion media. The stability with time and temperature of the biliprotein in the microemulsion was higher than in the aqueous solution. All the results can be explained in terms of B-PE inclusion in the water droplets of AOT microemulsions where the protein has similar configuration and conformation to that in aqueous solution but with the chromophores more protected.

Preparative purification of B-phycoerythrin from the microalga Porphyridium cruentum by expanded-bed adsorption chromatography

B-Phycoerythrin (B-PE) is a major light-harvesting pigment of microalgae. Due to its high fluorescence efficiency and its intense and unique pink color, it is widely used as a fluorescent probe and analytical reagent as well as being employed as a natural dye in foods and cosmetics. Tedious methodologies for B-PE purification have been published. In this work we present a new, fast, preparative and scaleable two-step chromatographic method for B-PE purification from the red microalga Porphyridium cruentum. Initially, phycobiliproteins were released from the microalga cells by osmotic shock and captured by applying the centrifuged cell suspension to a column containing 74 ml Streamline-DEAE equilibrated with 50 mM acetic acid-sodium acetate buffer, pH 5.5, using expanded-bed adsorption chromatography at an upward flow of 200 cm h(-1). After adsorption, washing was carried out in the expanded-bed mode. Having removed unbound proteins and cellular debris, the bed was allowed to sediment and a B-PE-rich solution was eluted with a downward flow of the same 250 mM buffer. In order to obtain pure B-PE, we utilized conventional ion-exchange chromatography with a column of DEAE-cellulose loaded directly with the eluate from Streamline-DEAE and developed using a discontinuous gradient of acetic acid-sodium acetate buffer, pH 5.5. With this new methodology, 66% of B-PE contained in the biomass of the microalgae was recovered, a value significantly higher than those obtained following other methodologies. The B-PE purity was tested using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and spectroscopic characterization.

Spanish population at risk of unwanted pregnancy: results of a national survey

OBJECTIVE

We performed a personal survey in 2218 Spanish women aged from 15 to 49 years to establish the contraceptive methods used by this population and to determine the number of Spanish women of childbearing age exposed to unwanted pregnancy.

METHODS

Stratified random sampling was performed to select the women to be interviewed; this sampling design ensured adequate representation of the sample in Spain.

RESULTS

At the time of the survey, 69.1% of the women were using some contraceptive method, but 5% of them used poorly effective contraceptive methods, and their exposure to the risk of an unwanted pregnancy was therefore high. Moreover, among the 30.9% not using any contraceptive method, 21.1% were at risk because they were having sexual intercourse, did not want to become pregnant and did not use a contraceptive method.

CONCLUSIONS

A little over one million Spanish women are exposed to the risk of having an unwanted pregnancy. Compiling the data on this significant problem is the first step in designing appropriate solutions.

Fluorescence energy transfer between fluorescein label and DNA intercalators to detect nucleic acids hybridization in homogeneous media

A general approach to detecting nucleic acid sequences in homogeneous media by means of steady-state fluorescence measurements is proposed. The methodology combines the use of a fluorescence-labeled single-strand DNA model probe, the complementary single-strand DNA target, and a DNA intercalator. The probe was fluorescein labeled to a spacer arm at the N4 position of the cytosine amino groups in polyribocytidylic acid (5'), poly(C), which acts as a model DNA probe. The complementary strand was polyriboinosinic acid (5'), poly(I), as a model of the target, and the energy transfer acceptor was an intercalator, either ethidium bromide or ethidium homodimer. In previous papers we have shown that the fluorescence intensity of the fluorescein label decreases when labeled poly(C) hybridizes with poly(I), and this fluorescence quenching can be used to detect DNA hybridization or renaturation in homogeneous media. In this paper we demonstrate that fluorescence resonance energy transfer (FRET) between fluorescein labeled to poly(C) and an intercalator agent takes place when single-stranded poly(C) hybridizes with poly(I), and we show how the fluorescence energy transfer further decreases the steady-state fluorescence intensity of the label, thus increasing the detection limit of the method. The main aim of this work was to develop a truly homogeneous detection system for specific nucleic acid hybridization in solution using steady-state fluorescence and FRET, but with the advantage of only having to label the probe with the energy donor since the energy acceptor is intercalated spontaneously. Moreover, the site label is not critical and can be labeled randomly in the DNA strand. Thus, the method is simpler than those published previously based on FRET. The experiments were carried out in both direct and competitive formats.

Discriminative whisking in the head-fixed rat: optoelectronic monitoring during tactile detection and discrimination tasks

We compared whisking movement patterns during acquisition of tactile detection and object discrimination under conditions in which (a) head movements are excluded and (b) exposure to tactile discriminanda is confined to the large, moveable vibrissae (macrovibrissae). We used optoelectronic instrumentation to track the movements of an individual whisker with high spatio-temporal resolution and a testing paradigm, which allowed us to dissociate performance on an "indicator" response (lever pressing) from the rat's "observing" responses (discriminative whisking). We analyzed the relation between discrimination performance and whisking movement patterns in order to clarify the process by which the indicator response comes under the stimulus control of information acquired by the rat's whisking behavior. Whisking patterns over the course of task acquisition differed with task demands. Acquisition of the Detection task was correlated with modulation of only one whisking movement parameter-total number of whisks emitted, and more whisking was seen on trials in which the discriminandum was absent. Discrimination between a sphere and cube differing in size and texture was correlated with a reduction in whisk duration and protraction amplitude and with a shift towards higher whisking frequencies. Our findings confirm previous reports that acquisition of tactile discriminations involves modulation by the animal of both the amount and the type of whisking. In contrast with a previous report (Brecht et al., 1997), they indicate that rats can solve tactile object detection and discrimination tasks (a) using only the large, motile mystacial vibrissae (macrovibrissae) and (b) without engaging in head movements. We conclude that the functional contribution of the macrovibrissae will vary with the nature of the task and the conditions of testing.

Protein interactions leading to conformational changes monitored by limited proteolysis: apo form and fragments of horse cytochrome c

Proteolysis experiments have been used to monitor the conformational transitions from an unfolded to a folded state occurring when the apo form of horse cytochrome c (cyt c) binds the heme moiety or when two fragments of cyt c form a native-like 1:1 complex. Proteinase K was used as a proteolytic probe, in view of the fact that the broad substrate specificity of this protease allows digestion at many sites along a polypeptide chain. The rather unfolded apo form of cyt c binds heme with a concomitant conformational transition to a folded species characterized by an enhanced content of helical secondary structure. While the holoprotein is fully resistant to proteolytic digestion and the apoprotein is digested to small peptides, the noncovalent complex of the apoprotein and heme exhibits an intermediate resistance to proteolysis, in agreement with the fact that the more folded structure of the complex makes the protein substrate more resistant to proteolysis. The noncovalent native-like complex of the two fragments 1-56 and 57-104 of cyt c, covering the entire polypeptide chain of 104 residues of the protein, is rather resistant to proteolysis, while the individual fragments are easily digested. Fragment 57-104 is fast degraded to several peptides, while fragment 1-56 is slowly degraded stepwise from its C-terminal end, leading initially mostly to fragments 1-48 and 1-40 and, at later stages of proteolysis, fragments 1-38, 1-35, 1-33, and 1-31. Thus, proteolysis data indicate that the heme containing fragment 1-56 has a rather compact core and a C-terminal flexible tail. Upon prolonged incubation of the complex of fragments 1-56 and 57-104 (nicked cyt c) with proteinase K, a chain segment is removed from the nicked protein, leading to a gapped protein complex of fragments of 1-48 and 57-104 and, on further digestion, fragments 1-40 and 57-104. Of interest, the chain segment being removed by proteolysis of the complex matches the omega-loop which is evolutionarily removed in cyt c of microbial origin. Overall, rates and/or resistance to proteolysis correlates well with the extent of folding of the protein substrates, as deduced from circular dichroism measurements. Thus, our results underscore the utility of proteolytic probes for analyzing conformational and dynamic features of proteins. Finally, a specific interest of the cyt c fragment system herewith investigated resides in the fact that the fragments are exactly the exon products of the cyt c gene.

Whisker deafferentation and rodent whisking patterns: behavioral evidence for a central pattern generator

Even in the absence of explicit stimulation, rats emit patterns of rhythmic whisking movements. Because of their stereotyped nature and their persistence after sensory denervation and cortical ablation, whisking movements have been assumed to reflect the output of a central pattern generator (CPG). However, identification of a movement pattern as the product of a CPG requires evidence that its generation, patterning, and coordination are independent of sensory input. To provide such evidence, we used optoelectronic instrumentation to obtain high-resolution records of the movement trajectories of individual whiskers in rats whose heads were fixed to isolate their exploratory whisking from exafferent inputs. Unconditioned whisking patterns were quantitatively characterized by a biometric analysis of the kinematics, rhythmicity, and coordination of bilaterally homologous vibrissa movements. Unilateral and bilateral sectioning of the infraorbital nerve, which innervates the whiskers, was then performed to block reafferent inputs generated by the animal's own whisking movements. Unilateral sectioning of the nerve has no effect on whisking kinematics but is followed by a significant but relatively transient bilateral increase in whisking frequency. However, bilateral deafferentation, when performed in a single-stage procedure, does not disrupt the generation, patterning, or bilateral coordination of whisking patterns in the rat. These findings provide strong behavioral evidence for a whisking CPG and are discussed in relation to its possible location and properties.

Chromatographic purification and characterization of B-phycoerythrin from Porphyridium cruentum. Semipreparative high-performance liquid chromatographic separation and characterization of its subunits

A fast preparative two-step chromatographic method for purification of B-phycoerythrin from Porphyridium cruentum is described. This biliprotein was homogeneous as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis yielding three closely migrating bands corresponding to its three subunits. Baseline separation of its alpha-, beta- and gamma-subunits was achieved by a reversed-phase HPLC gradient semipreparative method with a C4 large-pore column and a solvent system consisting of 0.05% trifluoroacetic acid (TFA) in water and 0.05% TFA in acetonitrile. B-Phycoerythrin in different aggregation states and its subunits have been spectroscopically characterized. Hexameric B-phycoerythrin has similar secondary and tertiary structure than dissociated B-phycoerythrin determined by circular dichroism.

Use of contraceptive methods in Spain: results of a national survey☆

We conducted a personal interview of 2136 Spanish women aged 15 to 49 years with the aim of determining the contraceptive attitudes of this population. A stratified random sampling was performed to select the women who were to be interviewed, and this sampling design ensured adequate representation of the sample in Spain. At the time of the survey, only 1296 of the 2136 women used some type of contraceptive method (60.6%); the most commonly used method was the condom. The major reason given by the 840 women not using contraceptive methods was the absence of sexual intercourse. Nearly 25% of the Spanish women aged 15-49 years reported that they have no sexual relations.

"Real-time" monitoring of vibrissa contacts during rodent whisking

Rodent whisking behavior provides active touch as input into a widely studied model system of information processing and behavior. We previously developed a simple optoelectronic system to monitor whisker movements in "real time" in head held rats at rest or performing various tasks such as tactile discrimination. We now describe a simple piezioelectic film device for detecting initial whisker contacts during whisking also in real time. In some applications this is as effective as high-speed videos and can be configured to isolate the contacts from different whiskers. The construction of this simple device is detailed. In addition to providing information during recordings from awake animals, the device could be used, for example, as an operant "manipulandum" for contingent reinforcement of object detection with a whisker.

[Fulminant streptococcus infection of soft tissue]

BACKGROUND

In recent years there has been an apparent increase in severe infections produced by group A beta-hemolytic Streptococci in developed countries. Necrotizing fascitis and myositis are two rare but fearsome complications caused by this microorganism.

METHODS

Two cases of fulminant soft tissue infection recently observed in the authors' center are presented and the clinical presentation and differential diagnosis commented upon.

RESULTS

The first case was a necrotizing fascitis at a surgical wound which appeared following a gynecological surgery. The second case reports gluteal myositis following intramuscular injection. In both cases the evolution was disastrous.

CONCLUSIONS

Streptococcus pyogenes may produce fulminant infections in patients without underlying disease either spontaneously or following minimum traumas. The most frequent involvement is of the soft tissues. This virulence at a local tissue and systemic level has been associated with the production of exotoxin.

Trigeminal deafferentation and conditioned pecking in pigeons

To clarify the contribution of peripheral trigeminal input to the control of pecking behavior we examined head and jaw movement kinematics and peck localization in pigeons with surgical section of trigeminal nerves providing somatosensory input to the beak. Conditioning procedures were used to bring the pecking/grasping components of pecking under the control of a visual target. Conditioned head and jaw movements were monitored 'on-line' using movement transducers and terminal peck location was recorded using 'touch-screen' technology. The periodic delivery of a food reinforcer provided repeated opportunities to monitor the kinematics of ingestive pecks. Deafferentation produced deficits in mandibulation during ingestive pecking and in the coordination of head and jaw movements during conditioned pecking. These results are attributed to disruptions in trigeminal feedback and feedforward mechanisms, respectively. In contrast with previous studies, deafferentation did not impair the precision of peck localization. Possible reasons for the absence of localization deficits are presented. The results are discussed in relation to the role of peripheral inputs in the control of prehensile movements.

Optoelectronic monitoring of individual whisker movements in rats

We describe two systems for the real-time recording and display of individual vibrissa movements in head-fixed rats. Both systems utilize high-speed, linear image sensors, each composed of an array of light sensitive elements (CCDs). Uniform illumination of the array generates a constant baseline voltage in each element. The shadow produced by the movement of a whisker interposed between the light source and the sensors produces a voltage shift in a subset of elements. The successive position of the shift is linearly related to the momentary whisker position. Associated software/hardware scans the array at regular intervals to identify the successive positions of voltages above a preset threshold and outputs the data to a microprocessor for computation of the whisker movement trajectory. In both systems, movements of a single whisker may be monitored 'on-line' with high spatial and temporal resolution; in one case with, in the other without the presence of neighboring whiskers. Optoelectronic monitoring facilitates rapid and efficient (computer-assisted) acquisition and analysis of data on rodent whisking behavior.