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1.
Aquaporins (AQPs) are a family of channel proteins, which transport water and/or small solutes across cell membranes. AQPs are present in Bacteria, Eukarya, and Archaea. The classical AQP evolution paradigm explains the inconsistent phylogenetic trees by multiple transfer events and emphasizes that the assignment of orthologous AQPs is not possible, making it difficult to integrate functional information. Recently, a novel phylogenetic framework of eukaryotic AQP evolution showed congruence between eukaryotic AQPs and organismal trees identifying 32 orthologous clusters in plants and animals (Soto et al. Gene 503:165–176, 2012). In this article, we discuss in depth the methodological strength, the ability to predict functionality and the AQP community perception about the different paradigms of AQP evolution. Moreover, we show an updated review of AQPs transport functions in association with phylogenetic analyses. Finally, we discuss the possible effect of AQP data integration in the understanding of water and solute transport in eukaryotic cells.  相似文献   
2.
Araucaria trees as host plants of the longhorned beetle Huequenia livida (Coleoptera: Cerambycidae) in Argentina are reviewed. Araucaria araucana is its natural host plant in SW Argentina, but the larvae also developed in dead branches of A. angustifolia and A. bidwillii (new host plant records), when both plants were kept in the same rearing cage with the natural host plant. Pinus contorta var. murrayana, also mentioned from Argentina, may be a recently adopted secondary host. A winter and a summer generation of H. livida was documented for the first time. Huequenia livida exceeds the actual natural distribution of A. araucana following the distribution of cultivated A. araucana and Pinus trees.  相似文献   
3.
Unique species of ceramide (Cer) with very-long-chain polyunsaturated fatty acid (VLCPUFA), mainly 28–32 carbon atoms, 4–5 double bonds, in nonhydroxy and 2-hydroxy forms (n-V Cer and h-V Cer, respectively), are generated in rat spermatozoa from the corresponding sphingomyelins during the acrosomal reaction. The aim of this study was to determine the properties of these sperm-distinctive ceramides in Langmuir monolayers. Individual Cer species were isolated by HPLC and subjected to analysis of surface pressure, surface potential, and Brewster angle microscopy (BAM) as a function of molecular packing. In comparison with known species of Cer, n-V Cer and h-V Cer species showed much larger mean molecular areas and increased molecular dipole moments in liquid expanded phases, which suggest bending and partial hydration of the double bonded portion of the VLCPUFA. The presence of the 2-hydoxyl group induced a closer molecular packing in h-V Cer than in their chain-matched n-V Cer. In addition, all these Cer species showed liquid-expanded to liquid-condensed transitions at room temperature. Existence of domain segregation was confirmed by BAM. Additionally, thermodynamic analysis suggests a phase transition close to the physiological temperature for VLCPUFA-Cers if organized as bulk dispersions.  相似文献   
4.
Mitochondrial hexokinase (HK) and creatine kinase (CK) known to form complexes with a voltage dependent anion channel (VDAC) have been reported to increase cell death resistance under hypoxia/anoxia. In this work we propose a new, non-Mitchell mechanism of generation of the inner and outer membrane potentials at anaerobic conditions. The driving force is provided by the Gibbs free energy of the HK and CK reactions associated with the VDAC–HK and the ANT (adenine nucleotide translocator)–CK–VDAC complexes, respectively, both functioning as voltage generators. In the absence of oxygen, the cytosolic creatine phosphate can be directly used by the ANT–CK–VDAC contact sites to produce ATP from ADP in the mitochondrial matrix. After that, ATP released through the fraction of unbound ANTs in exchange for ADP is used in the mitochondrial intermembrane space by the outer membrane VDAC–HK electrogenic complexes to convert cytosolic glucose into glucose-6-phosphate. A simple computational model based on the application of Ohm's law to an equivalent electrical circuit showed a possibility of generation of the inner membrane potential up to − 160 mV, under certain conditions, and of relatively high outer membrane potential without wasting of ATP that normally leads to cell death. The calculated membrane potentials depended on the restriction of ATP/ADP diffusion in narrow cristae and through the cristae junctions. We suggest that high inner membrane potential and calcium extrusion from the mitochondrial intermembrane space by generated positive outer membrane potential prevent mitochondrial permeability transition, thus allowing the maintenance of mitochondrial integrity and cell survival in the absence of oxygen.  相似文献   
5.
Sticholysin I (St I) is a pore-forming toxin (PFT) produced by the Caribbean Sea anemone Stichodactyla helianthus belonging to the actinoporin protein family, a unique class of eukaryotic PFT exclusively found in sea anemones. As for actinoporins, it has been proposed that the presence of sphingomyelin (SM) and the coexistence of lipid phases increase binding to the target membrane. However, little is known about the role of membrane structure and dynamics (phase state, fluidity, presence of lipid domains) on actinoporins' activity or which regions of the membrane are the most favorable platforms for protein insertion. To gain insight into the role of SM on the interaction of St I to lipid membranes we studied their binding to monolayers of phosphatidylcholine (PC) and SM in different proportions. Additionally, the effect of acyl chain length and unsaturation, two features related to membrane fluidity, was evaluated on St I binding to monolayers. This study revealed that St I binds and penetrates preferentially and with a faster kinetic to liquid-expanded films with high lateral mobility and moderately enriched in SM. A high content of SM induces a lower lateral diffusion and/or liquid-condensed phases, which hinder St I binding and penetration to the lipid monolayer. Furthermore, the presence of lipid domain borders does not appear as an important factor for St I binding to the lipid monolayer.  相似文献   
6.
We document and compare the annual molt of the Pacific harbor seal (Phoca vitulina richardii) on two islands off the west coast of the Baja California Peninsula that are the northern and southern extremes of its distribution in Mexico. During 2014, observations were made from March to July on Todos Santos Island (northern extreme) and from January to June on San Roque Island (southern extreme). On Todos Santos, the premolt lasted 15 wk (March–June) and the molt 12 wk (April–July). On San Roque, the premolt lasted 22 wk (January–June) and the molt 17 wk (February–June). The proportion of seals undergoing molt peaked on 26 May on Todos Santos and on 7 June on San Roque. Shedding of old hair most commonly initiated on the torso and progressed to the head and flippers (reverse molting pattern). The period when the highest number of harbor seals haul out in Mexico is in late April on the more southerly islands and in early May on the more northerly islands, when a large proportion of seals are in premolt.  相似文献   
7.
1. Temperature and oxygen are recognised as the main drivers of altitudinal limits of species distributions. However, the two factors are linked, and both decrease with altitude, why their effects are difficult to disentangle. 2. This was experimentally addressed using aquatic macroinvertebrates; larvae of Andesiops (Ephemeroptera), Claudioperla, (Plecoptera), Scirtes (Coleoptera) and Anomalocosmoecus (Trichoptera), and the amphipod Hyalella in an Ecuadorian glacier‐fed stream (4100–4500 m a.s.l.). The following were performed: (i) quantitative benthic sampling at three sites to determine altitudinal patterns in population densities, (ii) transplants of the five taxa upstream of their natural altitudinal limit to test the short‐term (14 days) effect on survival, and (iii) in situ experiments of locomotory activity as a proxy for animal response to relatively small differences in temperature (5 °C vs. 10 °C) and oxygen saturation (55% vs. 62%). 3. The transplant experiment reduced survival to a varying degree among taxa, but Claudioperla survived well at a site where it did not naturally occur. In the in situ experiment, Scirtes and Hyalella decreased their activity at lower oxygen saturation, whereas Andesiops and Anomalocosmoecus did so at a low temperature. The decrease in activity from a high to a low temperature and oxygen for the five taxa was significantly correlated with their mortality in the transplant experiment. 4. Together the present experiments indicate that even relatively small differences in temperature and oxygen may produce effects explaining ecological patterns, and depending on the taxon, either water temperature or oxygen saturation, without clear interacting effects, are important drivers of altitudinal limits.  相似文献   
8.
Removal of feral cats from island environments is a useful mechanism by which their ecological impact on endangered species can be reduced or ended. Nevertheless, because cats are anthropogenic in their origins, social perceptions of management practices play a large role in their implementation. Four-hundred questionnaires were delivered (386 were returned) with 100 going to each of the following: local residents; environmental workers; tourists; and, hunters. Questions explored respondents’ knowledge about island biodiversity and invasive species as well as attitudes towards cat population management methods. Habitat destruction and introduction of invasive species were considered the main threats for the conservation of island biodiversity. Most respondents considered cats to have a negative impact on biodiversity and sterilization campaigns were considered most appropriate for cat population control. Several free sterilization campaigns have been conducted in La Palma Island Biosphere Reserve in order to reduce free-ranging cats and were well received by local people. This research, which combined concepts of management, ecology and social sciences, provides valuable insights which may to be applicable on several other islands where cats and people are present and in conflict with conservation priorities.  相似文献   
9.
Understanding the genetic basis of sex determination mechanisms is essential for improving the productivity of farmed aquaculture fish species like turbot (Scophthalmus maximus). In culture conditions turbot males grow slower than females starting from eight months post-hatch, and this differential growth rate is maintained until sexual maturation is reached, being mature females almost twice as big as males of the same age. The goal of this study was to identify sex-specific DNA markers in turbot using comparative random amplified polymorphism DNA (RAPD) profiles in males and females to get new insights of the genetic architecture related to sex determination. In order to do this, we analyzed 540 commercial 10-mer RAPD primers in male and female pools of a gynogenetic family because of its higher inbreeding, which facilitates the detection of associations across the genome. Two sex-linked RAPD markers were identified in the female pool and one in the male pool. After the analysis of the three markers on individual samples of each pool and also in unrelated individuals, only one RAPD showed significant association with females. This marker was isolated, cloned and sequenced, containing two sequences, a microsatellite (SEX01) and a minisatellite (SEX02), which were mapped in the turbot reference map. From this map position, through a comparative mapping approach, we identified Foxl2, a relevant gene related to initial steps of sex differentiation, and Wnt4, a gene related with ovarian development, close to the microsatellite and minisatellite markers, respectively. The position of Foxl2 and Wnt4 was confirmed by linkage mapping in the reference turbot map.  相似文献   
10.
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