Vesicle Volume Research Articles

Unitary Water Permeability Measurements via Lipid Vesicle Systems

Water transport across lipid membranes is fundamental to all forms of life and plays a major role in health and disease. It is becoming more and more apparent that not only typical water channels such as aquaporins facilitate water flux. Transporters1, ion channels2 or receptors can also act as highly permeable water channels. The efforts directed towards both a mechanistic understanding of water flow determinants and the development of water flow inhibitors would profit from reliable and accurate ways of measuring unitary water channel permeabilities pf. A standard way of doing so is to subject proteoliposomes to an osmotic gradient in a stopped-flow device: Fast recordings of scattered light intensity are converted into the time course of vesicle volume change. Some of the underlying empirical procedures misjudge pf by several hundred percent. The error may be amplified to reach orders of magnitude by miscounting the amount of purified and reconstituted water channels. We developed a method that allows accurate determination of pf based on (a) a precise count of channels per lipid vesicle1-3 by fluorescence correlation spectroscopy and (b) an adaptation of the Rayleigh-Gans-Debey equation to accurately acquire the water efflux from scattered light intensities. Here we demonstrate possible flaws of widely used simplifications and their impact on published pf values. 1. Horner, A. et al. J. Biol. Chem. 291, jbc.M115.706986 (2016). 2. Hoomann et al. Proc. Natl. Acad. Sci. U. S. A. 110, 10842-7 (2013). 3. Horner, A. et al.Sci. Adv. 1, 1-5 (2015).

Effect of feeding rumen-protected methionine on productive and reproductive performance of dairy cows.

The objectives of this study were to evaluate the effects of daily top-dressing (individually feeding on the top of the total mixed ration) with rumen-protected methionine (RPM) from 30 ± 3 until 126 ± 3 Days in milk on productive and reproductive performance in lactating dairy cows. A total of 309 lactating dairy Holstein cows (138 primiparous and 171 multiparous) were randomly assigned to treatment diets containing either RPM (21.2 g of RPM + 38.8 g of dried distillers grain; 2.34% Methionine [Met] of metabolizable protein [MP]) or Control (CON; 60 g of dried distillers grain; 1.87% Met of MP). Plasma amino acids were evaluated at the time of artificial insemination (AI) and near pregnancy diagnosis. Milk production and milk composition were evaluated monthly. Pregnancy was diagnosed on Day 28 (by Pregnancy-specific protein B [PSPB]), 32, 47, and 61 (by ultrasound) and sizes of embryonic and amniotic vesicle were determined by ultrasound on Day 33 after AI. Feeding RPM increased plasma Met at 6, 9, 12, and 18 hours after top-dressing with a peak at 12 hours (52.4 vs 26.0 μM; P < 0.001) and returned to basal by 24 hours. Cows fed RPM had a small increase in milk protein percentage (3.08 vs 3.00%; P = 0.04) with no differences on milk yield and milk protein yield. Additionally, in multiparous cows, RPM feeding increased milk protein (3.03 vs 2.95%; P = 0.05) and fat (3.45 vs 3.14%; P = 0.01) percentages, although no effects were observed in primiparous cows. In multiparous cows fed RPM, pregnancy loss was lower between Days 28 to 61 (19.6 [10/51] vs. 6.1% [3/49]; P = 0.03) or between Days 32 to 61 (8.9 [4/45] vs. 0 [0/0] %; P = 0.03), although, there was no effect of treatment on pregnancy loss in primiparous cows. Consistent with data on pregnancy loss, RPM feeding increased embryonic abdominal diameter (P = 0.01) and volume (P = 0.009) and amniotic vesicle volume (P = 0.04) on Day 33 of pregnancy in multiparous cows but had no effect on embryonic size in primiparous cows. Thus, the increase in plasma Met concentrations after feeding RPM was sufficient to produce a small increase in milk protein percentage and to improve embryonic size and pregnancy maintenance in multiparous cows. Further studies are needed to confirm these responses and understand the biological mechanisms that underlie these responses as well as the timing and concentrations of circulating Met that are needed to produce this effect.

Significant changes of T2 value in the peripheral zone and seminal vesicles after ejaculation.

To analyse the quantitative changes of the prostate and seminal vesicles (SV) on magnetic resonance imaging (MRI) after ejaculation. Ten healthy young males were enrolled for T2-weighted and T2 mapping MRI before and after two consecutive ejaculations. T2 values of the peripheral zone (PZ) and the central gland (CG) at the midgland of the prostate were compared before and after ejaculation, respectively. T2 values of the PZ at the apex and base were also compared before and after, respectively. Pre- and post-ejaculation SV volumes were compared. The Wilcoxon's signed rank test with Bonferroni adjustment was used for comparison. After ejaculation, T2 values of the PZ significantly decreased (mean, 119±20 vs. 105±21, p=0.002) while those of the CG did not significantly change at the midgland. At the apex, T2 values of the PZ also decreased significantly (mean, 114±9 vs. 94±7, p=0.002). On the other hand, T2 values of the PZ did not change at the base. SV volumes were significantly reduced after ejaculation (mean, 11.1±7.7mL vs. 7.2±6.7mL, p=0.002). Ejaculation decreases T2 values of the PZ at the midgland and apex, and reduces SV volumes. Abstinence periods should be considered in evaluating the prostate and SV on MRI. • T2 values decrease after ejaculation in the apical-mid peripheral zone. • Ejaculation does not affect T2 values of the central gland. • Volume of the seminal vesicles decreases after ejaculation. • An abstinence period should be considered before pelvic MRI in men.

The longitudinal effect of ejaculation on seminal vesicle fluid volume and whole-prostate ADC as measured on prostate MRI

ObjectiveTo prospectively investigate the longitudinal effect of ejaculatory abstinence on MRI-measured seminal vesicle (SV) volume and whole-prostate ADC over consecutive days.Methods15 healthy male volunteers (mean 35.9 years, range 27–53) underwent 3-T MRI at baseline and 1, 2 and 3 days post-ejaculation. Prostate and SV volumes were derived by volume segmentation and whole-gland apparent diffusion coefficient (ADC) values calculated. A mixed-effects linear regression compared ADC values and prostate/seminal vesicle volumes in each volunteer between studies in a pairwise manner.ResultsAll subjects completed the four MRIs. Mean prostate volume was 22.45 cm3 (range 13.04–31.21 cm3), with no change between the four studies (p = 0.89–0.99). 13/15 subjects showed SV volume reduction from baseline to day 1, with group-mean decreasing from 6.45 to 4.80 cm3 (−25.6%, p < 0.001), and a significant reduction from baseline to day 2 (−18.1%, p = 0.002). There was a significant volume increase from both day 1 (+21.3%, p = 0.006) and day 2 (+10.2%, p = 0.022) to day 3 post-ejaculation. There was a significant reduction in ADC from 1.105 at baseline to 1.056 × 10−3 mm2/s at day 1 (mean −4.3%, p = 0.009).ConclusionThe longitudinal effect of ejaculation on SV volume was demonstrated. Significant reductions in SV volume and whole-gland ADC were observed post-ejaculation, supporting a 3-day period of abstinence before prostate MRI.Key Points• Seminal vesicle volume significantly reduced 24 h post-ejaculation remaining reduced at day 2• Seminal vesicle fluid volume significantly increased from day 1 to day 3 post-ejaculation• There was a significant reduction in whole-gland prostate ADC values day 1 post-ejaculation• 3-day abstinence from ejaculation is required to ensure maximal seminal vesicle distension

Petrological studies of volcanic ash from Sakurajima volcano in 2013, Southern Kyushu, Japan

Many petrological studies of volcanic rocks have attempted to better predict future volcanic activity. In this study, we examined volcanic ash samples from Showa Crater in Sakurajima, Japan, which were erupted from January to October 2013. This study was used two types of juvenile material; black vesicular volcanic rock (BVVR) and black non-vesicular volcanic rock (BNVVR) to determine the variable of magmatic processes in the magma conduit during the 2013 eruption. We divided the duration into three periods such as January to April, April to July, and July to October based on the variable tendency of SiO2 contents and volume abundance of the interstitial glasses in BVVR and BNVVR. The estimated melt compositions demonstrate that the variability of SiO2 contents and volume abundance of microcrystal in the groundmass (BVVR and BNVVR) over time were caused by micro-crystallization processes. The estimated of water contents and vesicle volume shows the influence of degassing process in the rock forming. Also, the correlation of petrological features with the number of eruptions and eruptive volumes, exhibit the variable of magma supply into conduit in each period. Consequently, careful monitoring of the petrological features of erupted materials may provide useful constraints on future eruptive activity and thereby assist in the mitigation of volcanic hazards.

Growth and instability of a phospholipid vesicle in a bath of fatty acids

Using a microfluidic trap, we study the behavior of individual phospholipid vesicles in contact with fatty acids. We show that spontaneous fatty acids insertion inside the bilayer is controlled by the vesicle size, osmotic pressure difference across the membrane and fatty acids concentration in the external bath. Depending on these parameters, vesicles can grow spherically or become unstable and fragment into several daughter vesicles. We establish the phase diagram for vesicle growth and we derive a simple thermodynamic model that reproduces the time evolution of the vesicle volume. Finally, we show that stable growth can be achieved on an artificial cell expressing a simple set of bacterial cytoskeletal proteins, paving the way toward artificial cell reproduction.

Anatomical Study of Male Reproductive Organs of the Indonesian Short-Nosed Fruit Bat (Cynopterus titthaecheilus Temminck, 1825)

Bats are one of the mammals of Chiroptera order. Chiroptera Order has two sub-orders, Megachiroptera and Microchiroptera. One of the species of Megachiroptera is &lt;em&gt;Cynopterus titthaecheilus&lt;/em&gt; (&lt;em&gt;C. titthaecheilus&lt;/em&gt;). Local name for &lt;em&gt;C. titthaecheilus&lt;/em&gt; is the Indonesian short-nosed fruit &lt;em&gt;bat&lt;/em&gt;. Characteristics of &lt;em&gt;C. titthaecheilus&lt;/em&gt; are dark brown body hair and no tragus in the ear. Population of &lt;em&gt;C. titthaecheilus&lt;/em&gt; in Indonesia are relatively abundant, but research about anatomy of male reproduction organs of this species is still rare. The purpose of this study was to determine the anatomical features of male &lt;em&gt;C. tittahecheilus&lt;/em&gt; reproductive organs. Observations of macroscopic anatomy include observation of morphology, size, weight and volume of penis, testiscle, epididymis, vas defferens, prostate and seminal vesicles. Observation on microscopical anatomy of male reproduction organ is using histological slide preparations stained by &lt;em&gt;Hematoxylin-Eosin&lt;/em&gt;.

Machinery Mediating Kiss‐and‐Run Mechanism of Cell Secretion

Secretion is a fundamental cellular process in living organisms, from yeast to cells in humans. Since the 1950's, it was believed that secretory vesicles completely merged with the cell plasma membrane during secretion. While this may occur, the observation of partially empty vesicles in cells following secretion suggests the presence of transient or so called ‘kiss‐and‐run’ mechanism that allows fractional discharge of intra‐vesicular contents during secretion. This proposed mechanism is mediated by a supramolecular cup‐shaped structure at the plasma membrane called ‘porosome’, which enable secretory vesicles to transiently fuse with the plasma membrane, expel a portion of its contents, and disengage. Porosomes range in size from 15 nm in neurons and astrocytes, to 180 nm in endocrine and exocrine cells. Neuronal porosomes are composed of nearly 40 proteins, compared to the 120 nm nuclear pore complex of &gt;500 protein molecules. Porosome structure, its chemical composition, and functional reconstitution into artificial lipid membrane, and the molecular assembly of membrane‐associated t‐SNARE and v‐SNARE proteins in a ring or rosette complex to establish the fusion pore at the porosome base, and the molecular mechanism of secretory vesicle volume increase required for intravesicular content release during cell secretion, collectively provide a molecular understanding of cell secretion, resulting in a paradigm‐shift in our understanding of the process.Support or Funding InformationWork presented in this article was supported in part by the National Science Foundation grants EB00303, CBET1066661 (BPJ)

Photoinduced Fusion of Lipid Bilayer Membranes.

We have developed a novel system for photocontrol of the fusion of lipid vesicles through the use of a photosensitive surfactant containing an azobenzene moiety (AzoTAB). Real-time microscopic observations clarified a change in both the surface area and internal volume of vesicles during fusion. We also determined the optimal cholesterol concentrations and temperature for inducing fusion. The mechanism of fusion can be attributed to a change in membrane tension, which is caused by the solubilization of lipids through the isomerization of AzoTAB. We used a micropipet technique to estimate membrane tension and discuss the mechanism of fusion in terms of membrane elastic energy. The obtained results regarding this novel photoinduced fusion could lead to a better understanding of the mechanism of membrane fusion in living cells and may also see wider applications, such as in drug delivery and biomimetic material design.

FIJI Macro 3D ART VeSElecT: 3D Automated Reconstruction Tool for Vesicle Structures of Electron Tomograms

Automatic image reconstruction is critical to cope with steadily increasing data from advanced microscopy. We describe here the Fiji macro 3D ART VeSElecT which we developed to study synaptic vesicles in electron tomograms. We apply this tool to quantify vesicle properties (i) in embryonic Danio rerio 4 and 8 days past fertilization (dpf) and (ii) to compare Caenorhabditis elegans N2 neuromuscular junctions (NMJ) wild-type and its septin mutant (unc-59(e261)). We demonstrate development-specific and mutant-specific changes in synaptic vesicle pools in both models. We confirm the functionality of our macro by applying our 3D ART VeSElecT on zebrafish NMJ showing smaller vesicles in 8 dpf embryos then 4 dpf, which was validated by manual reconstruction of the vesicle pool. Furthermore, we analyze the impact of C. elegans septin mutant unc-59(e261) on vesicle pool formation and vesicle size. Automated vesicle registration and characterization was implemented in Fiji as two macros (registration and measurement). This flexible arrangement allows in particular reducing false positives by an optional manual revision step. Preprocessing and contrast enhancement work on image-stacks of 1nm/pixel in x and y direction. Semi-automated cell selection was integrated. 3D ART VeSElecT removes interfering components, detects vesicles by 3D segmentation and calculates vesicle volume and diameter (spherical approximation, inner/outer diameter). Results are collected in color using the RoiManager plugin including the possibility of manual removal of non-matching confounder vesicles. Detailed evaluation considered performance (detected vesicles) and specificity (true vesicles) as well as precision and recall. We furthermore show gain in segmentation and morphological filtering compared to learning based methods and a large time gain compared to manual segmentation. 3D ART VeSElecT shows small error rates and its speed gain can be up to 68 times faster in comparison to manual annotation. Both automatic and semi-automatic modes are explained including a tutorial.

238 Relationship Between Volume of the Seminal Vesicles and Sexual Activity in Middle-Aged Men

238 Relationship Between Volume of the Seminal Vesicles and Sexual Activity in Middle-Aged Men

Does Abstinence From Ejaculation Before Prostate MRI Improve Evaluation of the Seminal Vesicles?

The purpose of the present study is to determine whether abstinence from ejaculation before undergoing multiparametric prostate MRI increases seminal vesicle (SV) volume and therefore improves diagnostic interpretation of the SVs. This retrospective study included 238 patients who underwent 3-T MRI of the prostate over a 4-month period. Patients were requested to complete a questionnaire that asked how long it had been since their last ejaculation (i.e., < 3 days vs ≥ 3 days). Forty-two patients (mean patient age, 62.0 years) indicated that it had been less than 3 days since their last ejaculation and were designated as group 1, whereas the remainder indicated an interval of 3 days or more since their last ejaculation. A group of 42 age-matched subjects (mean patient age, 62.1 years) were randomly selected from the remaining 196 patients and were designated as group 2. SV volumes were measured manually. Two radiologists who were blinded to group assignment and patient characteristics scored the right and left SVs separately to determine diagnostic interpretability, which was scored on a 3-point scale as follows: a score of 1 denoted that the SVs were not dilated and the score was nondiagnostic, a score of 2 indicated that the SVs were not dilated but the score was diagnostic, and a score of 3 denoted that the SVs were dilated and the score was diagnostic. Volume differences and interpretability scores were analyzed using a t test. Interobserver agreement was analyzed using the Cohen kappa statistic. A separate analysis was performed to evaluate differences in diagnostic interpretability for patients 60 years and younger versus patients older than 60 years, by use of the chi-square test and relative risk ratio analysis. The right, left, and total SV volumes for group 1 were 3.1 mL, 2.9 mL, and 6.0 mL, respectively, whereas those for group 2 were 4.7 mL, 4.1 mL, and 8.8 mL, respectively (p = 0.011). The mean interpretability scores for group 1 and group 2 were 2.0 and 2.5, respectively. For group 1, reader 1 and reader 2 assigned a nondiagnostic score for 10 and 13 patients, respectively, whereas for group 2, they assigned a nondiagnostic score for two and five patients, respectively (p = 0.01, for reader 1; and p = 0.03, for reader 2). For men in group 1 who were older than 60 years, reader 1 and reader 2 gave a nondiagnostic score for nine and 11 patients, respectively; whereas for men in group 2 who were older than 60 years, the readers gave a nondiagnostic score for two and five patients, respectively (p = 0.01, for reader 1; and p = 0.05, for reader 2). For men older than 60 years, abstinence from ejaculation for 3 or more days before undergoing MRI examination resulted in larger SV volumes and lower rates of nondiagnostic evaluation and therefore might improve evaluation of SV invasion on multi-parametric MRI. The difference is less striking in men 60 years and younger.

Relationship between volume of the seminal vesicles and sexual activity in middle-aged men.

The relationship between volume of the seminal vesicles and the frequency of sex and sexual function in middle-aged men is not clear. This study included 81 patients who were diagnosed with localized prostate cancer. Volume of the seminal vesicles was examined using a volume analyser from computed tomography. Sexual function was subjectively evaluated using the Expanded Prostate Cancer Index Composite and Erection Hardness Score. The frequency of sex was surveyed using our original questionnaire. The mean±SD age of the patients was 67.7±5.3years. There was no relationship between the volume of seminal vesicles and age of the patients. Volume of the seminal vesicles in patients who answered that they had sexual activity at least once a year was significantly larger than in those who answered no sexual activity for several years (P<.01) Moreover, among sexually active, middle-aged men, volume of the seminal vesicles was significantly larger in those who had a sexual frequency once every 3months than in those who had a sexual frequency once every 6months or once a year (P<.05). Our study suggests that the volume of seminal vesicles of middle-aged men is correlated with sexual activity.

A two phase field model for tracking vesicle-vesicle adhesion.

A multi-phase-field model for simulating the adhesion between two vesicles is constructed. Two phase field functions are introduced to simulate each of the two vesicles. An energy model is defined which accounts for the elastic bending energy of each vesicle and the contact potential energy between the two vesicles; the vesicle volume and surface area constraints are imposed using a penalty method. Numerical results are provided to verify the efficacy of our model and to provide visual illustrations of the different types of contact. The method can be adjusted to solve endocytosis problems by modifying the bending rigidity coefficients of the two elastic bending energies. The method can also be extended to simulate multi-cell adhesions, one example of which is erythrocyte rouleaux. A comparison with laboratory observations demonstrates the effectiveness of the multi-phase field approach.

Water Transport by the Sodium Glucose Cotransporter SGLT1

The small intestine reabsorbs about 8L of fluid daily by a yet unknown mechanism. In contrast to vectorial water transport in the kidney, intestinal water reabsorption is not mediated by aquaporins. The sodium-glucose cotransporter SGLT1 was implicated to play a crucial role because it (i) functions as a molecular water pump or (ii) provides a water channel. Here we tested both hypotheses by overexpressing SGLT1 in MDCK cell monolayers. Fluorescence correlation spectroscopy served to assess the unitary water channel permeability pf of SGLT1 in life cells by measuring (i) the dilution of an aqueous dye in the immediate monolayer vicinity and (ii) SGLT1 plasma membrane abundance1. pf agreed well the one obtained from deflation kinetics of proteoliposomes. We derived vesicle volume from the intensity of scattered light via our new adaptation of the Rayleigh-Gans-Debye equation2 and the number of the reconstituted SGLT1 molecules per vesicle via fluorescence correlation spectroscopy3. SGLT1's pf is comparable to the pf of aquaporins rendering (i) an intracellular pathway plausible and (ii) water pumping against the osmotic gradient physiologically meaningless as the passive backflux would be orders of magnitude larger.Funding: This work was supported by grant P23574 of the Austrian Science Fund to P.P.1. Erokhova, L., Horner, A., Kugler, P., and Pohl, P. (2011). Monitoring single-channel water permeability in polarized cells. J. Biol. Chem. 286, 39926-39932.2. Hoomann, T., Jahnke, N., Horner, A., Keller, S., and Pohl, P. (2013). Filter gate closure inhibits ion but not water transport through potassium channels. PNAS 110, 10842-10847.3. Horner, A., Zocher, F., Preiner, J., Ollinger, N., Siligan, C., Akimov, S.A., and Pohl, P. (2015). The mobility of single-file water molecules is governed by the number of H-bonds they may form with channel-lining residues. Science Advances 1, e1400083.

110 TREATMENT WITH GnRH ON DAY 5 REDUCES PREGNANCY LOSS IN HEIFERS RECEIVING IN VITRO-PRODUCED EXPANDED BLASTOCYSTS

The hypothesis was that GnRH on Day 5 of a synchronized cycle in embryo transfer recipients would increase progesterone (P4) concentrations, embryo size, and fertility. Holstein and cross-bred Holstein heifers (n = 1562) were synchronized using a modified 5-day CIDR Co-Synch as follows: Day –8 CIDR inserted; Day –3 CIDR removed; prostaglandin F2α treatment; Day –2 second prostaglandin F2α; Day 0 gonadotropin-releasing hormone (G1, 100 μg of gonadorelin acetate) to induce ovulation. On Day 5.5, heifers were assigned in a completely randomised design to 1 of 2 treatments: Control (untreated) or GnRH (200 μg of gonadorelin acetate). Transfer of fresh in vitro-produced embryos was performed between d 6 and 8 after G1. Data collected from each heifer included embryo stage and quality, body condition score, technician, interval from G1 to transfer, and number of previous transfers. All heifers were evaluated by transrectal ultrasonography on Day 5, 33, and 62 and a subset of heifers was scanned on Day 12 (n = 718; to determine ovulation to treatment) and another subset on Day 33 (n = 296; 16-s video to determine embryo and amniotic vesicle size). Serum P4 was determined from a subset of heifers on Day 12 (n = 467). Fertility data were analysed by logistic regression (LOGISTIC procedure, SAS 9.4), whereas continuous outcomes were analysed by ANOVA (MIXED procedure). Ovulation to Day 5.5 gonadotropin-releasing hormone was 83.9% (302/360) in GnRH-treated heifers v. 3.3% (12/358) in Control (P &lt; 0.001). Progesterone on Day 12 was greater in GnRH-treated heifers 7.2 ± 0.1 ng mL–1 v. Controls 6.0 ± 0.1 ng mL–1 (P &lt; 0.001). There was an effect of embryo stage at Day 33 and 60 of pregnancy, with Stage 7 having greater P/ET than Stage 6 embryos. Treatment with GnRH did not alter pregnancy per embryo transfer with either embryo stage but decreased pregnancy loss in Stage 7 embryos, as shown in Table 1. Embryo size measured as crown-rump length (CRL) did not differ, as shown in Table 1. Similarly, amniotic vesicle volume (AVV) was not different between GnRH (549.1 ± 16 mm3) and Control (543.5 ± 14 mm3; P = 0.86), nor was there an interaction between treatment and embryo stage (P = 0.71). In addition, neither AVV (P = 0.22) nor CRL (P = 0.41) were associated with pregnancy loss between Day 33 and 60. In conclusion, treatment with GnRH on Day 5 resulted in increased P4 and a reduction in pregnancy loss in heifers receiving a Stage 7 embryo without changing conceptus size. Table 1.Pregnancies per embryo transfer (P/ET), crown-rump length (CRL), and pregnancy loss in embryo recipients receiving gonadotropin-releasing hormone (GnRH) on Day 5.5 v. control

Patterns of Flexible Nanotubes Formed by Liquid-Ordered and Liquid-Disordered Membranes.

Biological membranes form both intra- and intercellular nanotubes that are used for molecular sorting within single cells and for long-distance connections between different cells. Such nanotubes can also develop from synthetic lipid bilayers in their fluid state. Each nanotube has a large area-to-volume ratio and stably encloses a water channel that is thereby shielded from its surroundings. The tubes are rather flexible and can easily change both their length and their conformation. Here, we study nanotubes formed by liquid-ordered (Lo) and liquid-disordered (Ld) membranes with three lipid components exposed to aqueous mixtures of two polymers, polyethylene glycol (PEG) and dextran. Both types of membranes form striking patterns of nanotubes when we reduce the volume of giant vesicles by osmotic deflation, thereby exposing the two bilayer leaflets of the membranes to polymer solutions of different composition. With decreasing volume, three different patterns are observed corresponding to three distinct vesicle morphologies that reflect the interplay of spontaneous curvature and aqueous phase separation. We show that tube nucleation and growth is governed by two kinetic pathways and that the tubes undergo a novel shape transformation from necklace-like to cylindrical tubes at a certain critical tube length. We deduce the spontaneous curvature generated by the membrane-polymer interactions from the observed vesicle morphologies using three different and independent methods of image analysis. The spontaneous curvature of the Ld membranes is found to be 4.7 times larger than that of the Lo membranes. We also show that these curvatures are generated by weak PEG adsorption onto the membranes, with a binding affinity of about 1.6 kBT per chain. In this way, our study provides a direct connection between nanoscopic membrane shapes and molecular interactions. Our approach is rather general and can be applied to many other systems of interest such as polymersomes or membrane-bound proteins and peptides.

The role of prolactin in andrology: what is new?

Prolactin (PRL) has been long deemed as a hormone involved only in female reproduction. However, PRL is a surprising hormone and, since its identification in the 1970s, its attributed functions have greatly increased. However, its specific role in male health is still widely unknown. Recently, low PRL has been associated with reduced ejaculate and seminal vesicle volume in infertile subjects. In addition, in men consulting for sexual dysfunction, hypoprolactinemia has been associated with erectile dysfunction and premature ejaculation, findings further confirmed in the general European population and infertile men. Several metabolic derangements, recapitulating metabolic syndrome, have also been associated with low PRL both in men with sexual dysfunction and from the general European population. In men with sexual dysfunction, followed-up for more than 4years, low PRL was identified as an independent predictor of the incidence of major adverse cardiovascular events. Finally, an association with anxiety or depressive symptoms has been found in men with sexual dysfunction and from the general European population. While a direct role for impaired PRL function in the pathogenesis of these reproductive, sexual, metabolic and psychological disorders is conceivable, the possibility that low PRL is a mirror of an increased dopaminergic or a decreased serotonergic tone cannot be ruled-out. Hyperactivity of the dopaminergic system can explain only a few of the aforementioned findings, whereas a hypo-serotonergic tone fits well with the clinical features associated with low PRL, and there is significant evidence supporting the hypothesis that PRL could be a mirror of serotonin in the brain.

Morphology and morphometry of the human embryonic brain: A three-dimensional analysis

The three-dimensional dynamics and morphology of the human embryonic brain have not been previously analyzed using modern imaging techniques. The morphogenesis of the cerebral vesicles and ventricles was analyzed using images derived from human embryo specimens from the Kyoto Collection, which were acquired with a magnetic resonance microscope equipped with a 2.35-T superconducting magnet. A total of 101 embryos between Carnegie stages (CS) 13 and 23, without apparent morphological damage or torsion in the brain ventricles and axes, were studied. To estimate the uneven development of the cerebral vesicles, the volumes of the whole embryo and brain, prosencephalon, mesencephalon, and rhombencephalon with their respective ventricles were measured using image analyzing Amira™ software. The brain volume, excluding the ventricles (brain tissue), was 1.15±0.43mm3 (mean±SD) at CS13 and increased exponentially to 189.10±36.91mm3 at CS23, a 164.4-fold increase, which is consistent with the observed morphological changes. The mean volume of the prosencephalon was 0.26±0.15mm3 at CS13. The volume increased exponentially until CS23, when it reached 110.99±27.58mm3. The mean volumes of the mesencephalon and rhombencephalon were 0.20±0.07mm3 and 0.69±0.23mm3 at CS13, respectively; the volumes reached 21.86±3.30mm3 and 56.45±7.64mm3 at CS23, respectively. The ratio of the cerebellum to the rhombencephalon was approximately 7.2% at CS20, and increased to 12.8% at CS23. The ratio of the volume of the cerebral vesicles to that of the whole embryo remained nearly constant between CS15 and CS23 (11.6–15.5%). The non-uniform thickness of the brain tissue during development, which may indicate the differentiation of the brain, was visualized with surface color mapping by thickness. At CS23, the basal regions of the prosencephalon and rhombencephalon were thicker than the corresponding dorsal regions. The brain was further studied by the serial digital subtraction of layers of tissue from both the external and internal surfaces to visualize the core region (COR) of the thickening brain tissue. The COR, associated with the development of nuclei, became apparent after CS16; this was particularly visible in the prosencephalon. The anatomical positions of the COR were mostly consistent with the formation of the basal ganglia, thalamus, and pyramidal tract. This was confirmed through comparisons with serial histological sections of the human embryonic brain. The approach used in this study may be suitable as a convenient alternative method for estimating the development and differentiation of the neural ganglia and tracts. These findings contribute to a better understanding of brain and cerebral ventricle development.

CO2 bubble generation and migration during magma–carbonate interaction

We conducted quantitative textural analysis of vesicles in high temperature and pressure carbonate assimilation experiments (1200 °C, 0.5 GPa) to investigate CO2 generation and subsequent bubble migration from carbonate into magma. We employed Mt. Merapi (Indonesia) and Mt. Vesuvius (Italy) compositions as magmatic starting materials and present three experimental series using (1) a dry basaltic-andesite, (2) a hydrous basaltic-andesite (2 wt% H2O), and (3) a hydrous shoshonite (2 wt% H2O). The duration of the experiments was varied from 0 to 300 s, and carbonate assimilation produced a CO2-rich fluid and CaO-enriched melts in all cases. The rate of carbonate assimilation, however, changed as a function of melt viscosity, which affected the 2D vesicle number, vesicle volume, and vesicle size distribution within each experiment. Relatively low-viscosity melts (i.e. Vesuvius experiments) facilitated efficient removal of bubbles from the reaction site. This allowed carbonate assimilation to continue unhindered and large volumes of CO2 to be liberated, a scenario thought to fuel sustained CO2-driven eruptions at the surface. Conversely, at higher viscosity (i.e. Merapi experiments), bubble migration became progressively inhibited and bubble concentration at the reaction site caused localised volatile over-pressure that can eventually trigger short-lived explosive outbursts. Melt viscosity therefore exerts a fundamental control on carbonate assimilation rates and, by consequence, the style of CO2-fuelled eruptions.