European Lampreys: New Insights on Postglacial Colonization,Gene Flow and Speciation

Ice ages are known to be the most dominant palaeoclimatic feature occurring on Earth, producing severe climatic oscillations and consequently shaping the distribution and the population structure of several species. Lampreys constitute excellent models to study the colonization of freshwater systems, as they commonly appear in pairs of closely related species of anadromous versus freshwater resident adults, thus having the ability to colonize new habitats, through the anadromous species, and establish freshwater resident derivates. We used 10 microsatellite loci to investigate the spatial structure, patterns of gene flow and migration routes of Lampetra populations in Europe. We sampled 11 populations including the migratory L. fluviatilis and four resident species, L. planeri, L. alavariensis, L. auremensis and L. lusitanica, the last three endemic to the Iberian Peninsula. In this southern glacial refugium almost all sampled populations represent a distinct genetic cluster, showing high levels of allopatric differentiation, reflecting long periods of isolation. As result of their more recent common ancestor, populations from northern Europe are less divergent among them, they are represented by fewer genetic clusters, and there is evidence of strong recent gene flow among populations. These previously glaciated areas from northern Europe may have been colonized from lampreys expanding out of the Iberian refugia. The pair L. fluviatilis/L. planeri is apparently at different stages of speciation in different locations, showing evidences of high reproductive isolation in the southern refugium, and low differentiation in the north.     

Impact of Renal Sympathetic Denervation on Left Ventricular Structure and Function at 1-Year Follow-Up

Background

Catheter-based sympathetic renal denervation (RDN) is a recent therapeutic option for patients with resistant hypertension. However, the impact of RDN in left ventricular (LV) mass and function is not completely established. Our aim was to evaluate the effects of RDN on LV structure and function (systolic and diastolic) in patients with resistant hypertension (HTN).

Methods and Results

From a single centre prospective registry including 65 consecutive patients with resistant HTN submitted to RDN between July-2011 and April-2015, 31 patients with baseline and 1-year follow-up echocardiogram were included in this analysis. Mean age was 65±7 years, 48% were males, 71% had type 2 diabetes. Most had hypertension lasting for more than 10 years (90%), and were being treated with a median number of 6 anti-hypertensive drugs, including 74% on spironolactone. At 1-year, there was a significant decrease both on office SBP (176±24 to 149±13mmHg, p<0.001) and DBP (90±14 to 79±11mmHg, p<0.001), and also in 24h ABPM SBP (150±20 to 132±14mmhg, p<0.001) and DBP (83±10 to 74±9mmHg, p<0.001). There was also a significant decrease in LV mass from 152±32 to 136±34g/m² (p<0.001), an increase in LV end diastolic volume (93±18 to 111±27 mL, p = 0.004), an increase in LV ejection fraction (65±9 to 68±9%, p = 0.001) and mitral valve E deceleration time (225±49 to 247±51ms, p = 0.015) at 1-year follow up. There were no significant changes in left atrium volume index or in the distribution of patients among the different left ventricle geometric patterns and diastolic function subgroups.

Conclusions

In this single centre registry of patients with resistant hypertension, renal denervation was associated with significant reduction in both office and ABPM blood pressure and a significant decrease in left ventricle mass evaluated by transthoracic echocardiogram at 1 year follow-up.     

The Severity of Visceral Leishmaniasis Correlates with Elevated Levels of Serum IL-6, IL-27 and sCD14

Background

Visceral leishmaniasis (VL) is a severe disease caused by infection with protozoa of the genus Leishmania. Classic VL is characterized by a systemic infection of phagocytic cells and an intense activation of the inflammatory response. It is unclear why 90% of infected individuals do not develop the disease while a minority develop the classical form. Furthermore, among those that develop disease, a small group progresses to more severe form that is unresponsive to treatment. The presence of inflammatory mediators in serum could theoretically help to control the infection. However, there is also a release of anti-inflammatory mediators that could interfere with the control of parasite multiplication. In this study, we took advantage of the spectrum of outcomes to test the hypothesis that the immune profile of individuals infected with Leishmania (L.) infantum is associated with the development and severity of disease.

Methodology/Principal Findings

Sera from patients with confirmed diagnosis of VL were evaluated for the presence of numerous molecules, and levels compared with healthy control and asymptomatic infected individuals.

Conclusions/Principal Findings

Although differences were not observed in LPS levels, higher levels of sCD14 were detected in VL patients. Our data suggest that L. infantum may activate the inflammatory response via CD14, stimulating a generalized inflammatory response with production of several cytokines and soluble molecules, including IFN-γ, IL-27, IL-10, IL-6 and sCD14. These molecules were strongly associated with hepatosplenomegaly, neutropenia and thrombocytopenia. We also observed that IL-6 levels greater than 200 pg/ml were strongly associated with death. Together our data reinforce the close relationship of IFN-γ, IL-10, IL-6, TNF-α and IL-27 in the immune dynamics of VL and suggest the direct participation of sCD14 in the activation of the immune response against L. infantum.     

Temperature-activity relationships of cation activation and ouabain inhibition of (Na+ + K+)-ATPase.

The nonlinear temperature-activity relationship of membrane preparations of (Na⁺ + K⁺)-ATPase gives rise to discontinuities in Arrhenius plots of this enzyme. The different apparent energies of activation of (Na⁺ + K⁺) — ATPase which are observed above and below the critical temperature of the system have been considered to result from different conformational forms of the enzyme protein. Because both activation of (Na⁺ + K⁺)-ATPase by cations, and its specific inhibition by cardiac glycosides may be influenced by the conformational form of the enzyme protein, we have reexamined the effect of temperature upon the activation energy of the system under the different experimental conditions of cation activation and ouabain inhibition.Our results indicate that the activation of (Na⁺ + K⁺)-ATPase by cations, is less influenced by change in temperature than is inhibition of the enzyme by ouabain. In addition, mild lipolysis by phospholipase-A had a marked effect upon the ouabain-dependent response of the enzyme to temperature, but not upon the cation-dependent response. The effect of phospholipase-A can be overcome by reincubation of the treated preparation with phosphatidyl serine.We conclude that the ouabain-dependent temperature effects of (Na⁺ + K⁺)-ATPase are more dependent upon the integrity and nature of the membrane lipids than are the cation-dependent responses. It is possible that phosphatidyl serine plays a unique role in this regard.     

Electrically induced phase transitions via the dipole model in excitable membranes

Calculations based upon the membrane dipole model have been carried out and indicate the possibility of cooperative behavior during the membrane excitation process. An explicit expression is obtained for the critical electric field,E, which must be present to initiate the cooperative structural transition assumed to occur during membrane excitation. An hypothesis concerning the occurrence of two distinct phase transitions in the membrane resulting in the rapid influx of sodium ions and sodium ion inactivation, respectively, is presented.     

Behavior of triatomines (Hemiptera: Reduviidae) vectors of Chagas' disease. III. Influence of the number of matings on the fecundity and fertility of Panstrongylus megistus (Burm., 1835) in the laboratory

A study of the effect of mating in the fecundity and fertility of females of P. megistus fed on pigeon blood every 14 days, was carried out in the laboratory. Two groups were constituted: I - females which mated only once; II - females which stayed always with the males. Only 56.7% of group I females laid fertile eggs, while as much as 90% of group II females laid fertile eggs. The duration of the fertile oviposition was greater in the females which stayed always with the males. Some females of this group were able to mate up to seven times throughout their life-span. This fact render useless sterile males in the control of these insects.     

The testicular interstitial tissue of the amphibian Physalaemus fuscumaculatus

Summary The fine structure of the interstitial tissue of the testis of Physalaemus fuscumaculatus is described. Epithelioid cells identified as Leydig cells occur scattered in the interstitial tissue. Their cytoplasm contains a well developed smooth and rough surfaced endoplasmic reticulum arranged in whorls. The mitochondria present typical tubular cristae and unusual inclusions of a granular material. In spite of the distinctive characteristics reported here, it is assumed that the function of the Leydig cells is basically similar to that of the steroid synthetizing cells of the testicular interstitial tissue of higher vertebrates.An unusual feature is the presence of numerous melanophores randomly distributed in the capsule of the testis and in the interstitium. They are polyhedric cells with poorly developed organelles, numerous melanosomes, and long cytoplasmic processes.A large amount of collagen is present in the intercellular spaces closely related with undifferentiated cells, most of which are assumed to be fibroblasts.This work was supported by a Grant of the Consejo Nacional de Investigationes Científicas y Técnicas, and by Grant M-63-121 from the Population Council.Career investigators of the Consejo Nacional de Investigationes Científicas y Técnicas.Research Fellow of the same Institution.     

Activation energy and phospholipid requirements of membrane-bound adenosine triphosphatases

In order to evaluate the role of lipids in the function of membrane ATPase reactions, the apparent activation energies of membrane-bound (Na⁺ + K⁺)-ATPase and membrane-bound Mg²⁺-ATPase have been measured under conditions frequently supposed to alter the membrane lipids in vitro.In the case of (Na⁺ + K⁺)-ATPase, the untreated enzyme was shown to have two different activation energies as shown by an Arrhenius plot comprising two straight lines which intersect at the “critical temperature.” Treatment of the preparation with detergents or with phospholipase C causes some alteration in the spécifie activity of the enzyme but did not significantly alter the activation energies or the critical temperature. After treatment with phospholipase A, however, the Arrhenius plot appeared linear over the entire temperature range studied. Subsequent treatment of phospholipase A-treated preparations with phosphatidylserine restored the control response.Conversely, untreated preparations of Mg²⁺-ATPase give an Arrhenius plot which is neither linear nor composed of two intersecting straight lines. This plot, which we regard as curvilinear, does not permit a unique value of the activation energy to be determined. The shape of this plot is unaltered by detergent or by treatment with phospholipase C. In contrast to (Na⁺ + K⁺)-ATPase, it is also unaffected by treat-with phospholipase A or phospholipase A followed by phosphatidylserine.We conclude that although (Na⁺ + K⁺)-ATPase and Mg²⁺-ATPase are frequently closely associated in many membranes, their functions involve the presence of different membrane lipids.