Nuptial gift chemistry reveals convergent evolution correlated with antagonism in mating systems of harvestmen (Arachnida,Opiliones)

Nuptial gifts are material donations given from male to female before or during copulation and are subject to sexual selection in a wide variety of taxa. The harvestman genus Leiobunum has emerged as a model system for understanding the evolution of reproductive morphology and behavior, as transitions between solicitous and antagonistic modes of courtship have occurred multiple times within the lineage and are correlated with convergence in genital morphology. We analyzed the free amino acid content of nuptial gift secretions from five species of Leiobunum using gas chromatography–mass spectrometry. Multivariate analysis of the free amino acid profiles revealed that, rather than clustering based on phylogenetic relationships, nuptial gift chemical composition was better predicted by genital morphology and behavior, suggesting that convergent evolution has acted on the chemical composition of the nuptial gift. In addition, we found that, species with solicitous courtship produce gifts consisting of a 19% larger proportion of essential amino acids as compared to those with more antagonistic courtship interactions. This work represents the first comparative study of nuptial gift chemistry within a phylogenetic framework in any animal group and as such contributes to our understanding of the evolution of reproductive diversity and the participant role of nuptial gift chemistry in mating system transitions.     

Interactions between Glomus mosseae and arbuscular mycorrhizal sporocarp-associated saprophytic fungi

The saprophytic fungi Wardomyces inflatus (Marchal) Hennebert, Paecilomyces farinosus (Holm & Gray) A. H. S. Brown & G. Sm., Gliocladium roseum Bain., sterile dark mycelium (SDM-54), Trichoderma pseudokoningii Rifai and Trichoderma harzianum Rifai were isolated from sporocarps of Glomus mosseae. The effect of saprophytic fungi on G. mosseae spore germination was tested on water agar. Wardomyces inflatus decreased the percent germination of G. mosseae spores; G. roseum, T. pseudokoningii and T. harzianum had no effect on germination; and P. farinosus and SDM-54 increased the percentage of spore germination of G. mosseae after 4 d. Wardomyces inflatus significantly decreased hyphal length of spores which germinated, but no other saprophytic fungi affected hyphal growth. Trichoderma pseudokoningii, T. harzianum, P. farinosus and SDM-54 increased the number of auxiliary cells formed by G. mosseae. The effect of saprophytic fungi on arbuscular mycorrhizal colonization of soybean was studied in a greenhouse trial. The percentage of soybean root length colonized was decreased by W. inflatus, unaffected by SDM-54 and T. harzianum, and increased by P. farinosus. Gliocladium roseum decreased root length colonized when plants were 12 wk old, and T. pseudokoningii increased colonization of roots when plants were 4 wk old. Antagonistic, synergistic and neutral actions of G. mosseae upon the saprophytic fungi were observed. The population of T. harzianum decreased and the populations of T. pseudokoningii and SDM-54 increased in the presence of G. mosseae. Our results indicate a complex interaction between G. mosseae and associated saprophytic fungi.     

Nuclear Localization of p38 MAPK in Response to DNA Damage

p38 MAP kinase (MAPK) is activated in response to environmental stress, cytokines and DNA damage, and mediates death, cell differentiation and cell cycle checkpoints. The intracellular localization of p38 MAPK upon activation remains unclear, and may depend on the stimulus. We show here that activation of p38 MAPK by stimuli that induce DNA double strand breaks (DSBs), but not other stimuli, leads to its nuclear translocation. In addition, naturally occurring DSBs generated through V(D)J recombination in immature thymocytes also promote nuclear accumulation of p38 MAPK. Nuclear translocation of p38 MAPK does not require its catalytic activity, but is induced by a conformational change of p38 MAPK triggered by phosphorylation within the active site. The selective nuclear accumulation of p38 MAPK in response to DNA damage could be a mechanism to facilitate the phosphorylation of p38 MAPK nuclear targets for the induction of a G2/M cell cycle checkpoint and DNA repair.     

Measurements of Na+-occluded intermediates during the catalytic cycle of the Na+/K+-ATPase provide novel insights into the mechanism of Na+ transport

The Na⁺/K⁺-ATPase is an integral plasma membrane glycoprotein of all animal cells that couples the exchange of intracellular Na⁺ for extracellular K⁺ to the hydrolysis of ATP. The asymmetric distribution of Na⁺ and K⁺ is essential for cellular life and constitutes the physical basis of a series of fundamental biological phenomena. The pumping mechanism is explained by the Albers–Post model. It involves the presence of gates alternatively exposing Na⁺/K⁺-ATPase transport sites to the intracellular and extracellular sides and includes occluded states in which both gates are simultaneously closed. Unlike for K⁺, information is lacking about Na⁺-occluded intermediates, as occluded Na⁺ was only detected in states incapable of performing a catalytic cycle, including two Na⁺-containing crystallographic structures. The current knowledge is that intracellular Na⁺ must bind to the transport sites and become occluded upon phosphorylation by ATP to be transported to the extracellular medium. Here, taking advantage of epigallocatechin-3-gallate to instantaneously stabilize native Na⁺-occluded intermediates, we isolated species with tightly bound Na⁺ in an enzyme able to perform a catalytic cycle, consistent with a genuine occluded state. We found that Na⁺ becomes spontaneously occluded in the E1 dephosphorylated form of the Na⁺/K⁺-ATPase, exhibiting positive interactions between binding sites. In fact, the addition of ATP does not produce an increase in Na⁺ occlusion as it would have been expected; on the contrary, occluded Na⁺ transiently decreases, whereas ATP lasts. These results reveal new properties of E1 intermediates of the Albers–Post model for explaining the Na⁺ transport pathway.     

THE INTRACELLULAR MEMBRANES OF BLASTOMYCES DERMATITIDIS

Edwards , George A., and Mercedes R. Edwards . (Div. Labs, and Research, N.Y.S. Dept. of Health, Albany.) The intracellular membranes of Blastomyces dermatitidis. Amer. Jour. Bot. 47 (8): 622–632. Illus. 1960.—The yeast cells of Blastomyces dermatitidis have been studied in thin sections with the electron microscope. The cell is multinucleate, and the nuclei are frequently interconnected by their outer limiting membranes. The cell is bordered by a cell wall and the plasma membrane, which may be seen in direct continuity with the nuclear envelope. The cytoplasm contains numerous mitochondria, many profiles of the endoplasmic reticulum, and few multivesicular bodies. The membranes of all the constant cellular components are interconnected. Mitochondria appear to be formed from any of several membrane systems. The micromorphology of the cell suggests efficiency of communication and cytoplasmic mobility.     

LIFE HISTORY AND IN SITU GROWTH RATES OF ALEXANDRIUM TAYLORI (DINOPHYCEAE, PYRROPHYTA)

Alexandrium taylori Balech is a phototrophic marine dinoflagellate. It produced recurrent blooms during the summer months (July and August) of 1994 to 1997 in La Fosca beach (NW Mediterranean). In addition to a motile vegetative form, A. taylori had two benthic forms: temporary cysts and resting cysts. Temporary cysts were a temporally quiescent stage produced from the ecdysis of the vegetative cell in both natural populations and laboratory cultures. Temporary cysts may divide to form motile cells. Resting cysts had a thicker wall than the temporary cysts and had a red accumulation body. Gametes and planozygotes were also observed in laboratory cultures. Alexandrium taylori showed in situ diurnal vertical migration with an increase of vegetative cells in the water column in the morning through midday, with concentrations peaking in the afternoon followed by lower levels at night. Most vegetative cells lost their thecae and flagella, and with them their motility, turning into temporary cysts that settled in the early evening. The number of temporary cysts in the water column rose in the evening and at night. The temporary cysts gave rise to motile cells the following morning. Synthesis of DNA occurred in vegetative cells at night, and a preferential period of cell division occurred at sunrise. The estimated division rate in the field was 0.4–0.5 vegetative cells·day⁻¹. Temporary cysts had twice the DNA of a G₁ vegetative cell. The minimum in situ division rate of the temporary cysts was 0.14 day⁻¹. The role of the resting and temporary cyst population in the annual recurrence and maintenance of the A. taylori bloom is discussed.     

The assessment of sustainable tourism: Application to Spanish coastal destinations

This paper introduces an indicator system to evaluate sustainability in established coastal tourism destinations, applying the recommendations and definitions of the World Tourism Organization (WTO). We also develop a new synthetic indicator to simplify the measurement of sustainability and facilitate the comparative analysis of destination ranking. This measurement was obtained by applying a procedure to reduce the number of subjective decisions made by the analyst, using a novel two-stage aggregation methodology based on principal component analysis and on the distance to a reference point. The synthetic indicator obtained was applied to Spanish coastal destinations, and the results serve as a guideline for tourism planning. The conclusions of this research can be extrapolated to the study of other tourism destinations.     

Rosuvastatin protects isolated hearts against ischemia-reperfusion injury: role of Akt-GSK-3β, metabolic environment,and mitochondrial permeability transition pore

Journal of Physiology and Biochemistry - The cardioprotective activity of rosuvastatin (R) is yet to be known. The objective of this study was to research whether R perfusion before global ischemia...     

Diagnosis,Burden and Mortality of Pneumocystis jirovecii Pneumonia in Venezuela

Current Fungal Infection Reports - The aim of this work is to contribute to the knowledge of diagnosis, burden, and mortality of pneumocystosis or Pneumocystis jirovecii pneumonia (PCP) in...