Presynaptic endoplasmic reticulum architecture and hereditary spastic paraplegia

Hereditary spastic paraplegia(HSP)is a clinically and genetically heterogeneous neurodegenerative disorder,characterized primarily by progressive spasticity and weakness in the lower limbs.Pat ients can also experience peripheral neuropathy,cognitive impairment,and other neurological symptoms.To date,more than 80 genes have been implicated in HSP,encompassing various cellular components,although mutations in genes encoding endoplasmic reticulum(ER)-shaping proteins are the most prevalent(Parodi et al.,2017).ER-shaping proteins are generally known for regulating the tubulation and curvation of the ER,but most of them show additional functions,including fusion of ER tubules,microtubule-severing,ER autophagy,lipid droplet synthesis,contact sites with other organelles(Öztürk et al.,2020).This highlights the complexity of studying the role of these proteins and the link between ER function and HSP.

Role of vascular endothelial growth factor as a critical neurotrophic factor for the survival and physiology of motoneurons

Vascular endothelial growth factor(VEGF)was discovered by its angiogenic activity.However,during evolution,it appeared earlier as a neurotrophic factor required for the development of the nervous system in invertebrates lacking a circulatory system.We aimed at reviewing recent evidence indicating that VEGF has neuroprotective effects in neurons exposed to a variety of insults.Of particular interest is the link established between VEGF and motoneurons,especially after the design of the VEGFδ/δmutant mice.These mice are characterized by low levels of VEGF and develop muscle weakness and motoneuron degeneration resembling amyotrophic lateral sclerosis.The administration of VEGF through several routes to animal models of amyotrophic lateral sclerosis delays motor impairment and motoneuron degeneration and increases life expectancy.There are new recent advances in the role of VEGF in the physiology of motoneurons.Our experimental aims use the extraocular(abducens)motoneurons lesioned by axotomy as a model for studying VEGF actions.Axotomized abducens motoneurons exhibit severe alterations in their discharge activity and a loss of synaptic boutons.The exogenous administration of VEGF to axotomized abducens motoneurons,either from the transected nerve or intraventricularly,fully restores the synaptic and discharge properties of abducens motoneurons,despite being axotomized.In addition,when an anti-VEGF neutralizing antibody is delivered from the muscle to intact,uninjured abducens motoneurons,these cells display alterations in their discharge pattern and a loss of synaptic boutons that resemble the state of axotomy.All these data indicate that VEGF is an essential neurotrophic factor for motoneurons.

Avian malaria,haematocrit,and body condition in invasive wetland passerines settled in southwestern Spain

Avian malaria and related haemosporidian parasites can negatively impact fitness in many songbirds.Research on the malaria infection and its physiological costs on their avian hosts is heavily skewed toward native passerines,with exotic species underrepresented.However,introduced species may carry on and spread new pathogens to native species,and play a role on parasite transmission cycle in invaded bird communities as pathogen reservoir.Here,we molecularly assess the prevalence and diversity of haemosporidian parasites in three introduced wetland passerines(the Red Avadavat Amandava amandava,the Yellow-crowned Bishop Euplectes afer,and the Common Waxbill Estrilda astrild)captured during the same season in southwestern Spain.We also explored the relation between parasite infection,body condition,haematocrit,and uropygial gland volume.We detected an overall parasite prevalence of 3.55%,where Common Waxbills showed higher prevalence(6.94%)than Red Avadavats(1.51%).None Yellow-crowned Bishops were infected with haemosporidians.Almost 60%of infections were caused by Leucocytozoon,and about 40%by Plasmodium.We identified four unique lineages of Plasmodium and three of Leucocytozoon.Moreover,91%of the identified host-parasite interactions represented new host records for these haemosporidian parasites.Parasite infection was not related to body condition,haematocrit,and uropygial gland volume of the wetland passerines.Haematocrit values varied seasonally among bird species.Additionally,haematocrit was positively related to body condition in the Yellow-crowned Bishops,but not in the other species.Red Avadavats had higher haematocrit levels than Yellow-crowned Bishops,whereas Common Waxbills showed the lower haematocrit values.The uropygial gland volume was positively correlated with body condition in all bird species.Common Waxbills showed higher uropygial gland volumes related to their body size than birds from other two species.These outcomes highlight the importance of exotic invasive species in the transmission dynamics of haemosporidian parasites.

Proteomics for discovery of candidate colorectal cancer biomarkers

Colorectal cancer(CRC)is the second most common cause of cancer-related deaths in Europe and other Western countries,mainly due to the lack of wellvalidated clinically useful biomarkers with enough sensitivity and specificity to detect this disease at early stages.Although it is well known that the pathogenesis of CRC is a progressive accumulation of mutations in multiple genes,much less is known at the proteome level.Therefore,in the last years many proteomic studies have been conducted to find new candidate protein biomarkers for diagnosis,prognosis and as therapeutic targets for this malignancy,as well as to elucidate the molecular mechanisms of colorectal carcinogenesis.An important advantage of the proteomic approaches is the capacity to look for multiple differentially expressed proteins in a single study.This review provides an overview of the recent reports describing the different proteomic tools used for the discovery of new protein markers for CRC such as two-dimensional electrophoresis methods,quantitative mass spectrometry-based techniques or protein microarrays.Additionally,we will also focus on the diverse biological samples used for CRC biomarker discovery such as tissue,serum and faeces,besides cell lines and murine models,discussing their advantages and disadvantages,and summarize the most frequently identified candidate CRC markers.

神经干/祖细胞移植对脑损伤导致的胶质细胞活化有调节作用并有助于移植细胞与宿主胶质细胞间缝隙连接的建立

移植神经干/祖细胞有助于受损脑组织形态和功能的恢复。移植部位的微环境及移植细胞与宿主细胞间的通讯在神经干/祖细胞移植的神经保护机制中有重要意义。笔者既往研究显示,对中枢轴索损伤动物进行神经干/祖细胞移植有助于恢复损伤神经元的电活动及突触联系,并可增加神经营养因子的释放。本研究拟观察移植的神经干/祖细胞与宿主胶质细胞间的解剖关系,以探讨神经干/祖细胞移植的神经保护作用的可能机制。从新生大鼠的脑室下区提取神经干/祖细胞移植到内侧纵束横断伤模型大鼠脑内。移植后8周取脑进行相关检测。免疫组化检测结果显示,与未移植神经干/祖细胞的大鼠相比,移植了神经干/祖细胞的大鼠脑内更多的小胶质细胞被激活。移植的神经干/祖细胞聚集在激活的小胶质细胞和星形胶质细胞附近。缝隙连接蛋白CX-43表达在损伤部位的神经干/祖细胞和胶质细胞上,且较多的存在于移植细胞和胶质细胞相连接的部位。移植的神经干/祖细胞和宿主胶质细胞及宿主小胶质细胞间均形成了缝隙连接,但移植的神经干/祖细胞和宿主胶质细胞间的缝隙连接较多。本研究结果显示,神经干/祖细胞移植对脑损伤导致的胶质细胞活化有调节作用,并可能通过在移植细胞和宿主细胞间建立缝隙连接来调节细胞间的通讯,这可能是细胞移植的神经保护作用的机制之一。

Epigenetic regulation of stemness maintenance in the neurogenic niches

In the adult mouse brain, the subventricular zone lining the lateral ventricles and the subgranular zone in the dentate gyrus of the hippocampus are two zones that contain neural stem cells(NSCs) with the capacity to give rise to neurons and glia during the entire life of the animal. Spatial and temporal regulation of gene expression in the NSCs populationis established and maintained by the coordinated interaction between transcription factors and epigenetic regulators which control stem cell fate. Epigenetic mechanisms are heritable alterations in genome function that do not involve changes in DNA sequence itself but that modulate gene expression, acting as mediators between the environment and the genome. At the molecular level, those epigenetic mechanisms comprise chemical modifications of DNA such as methylation, hydroxymethylation and histone modifications needed for the maintenance of NSC identity. Genomic imprinting is another normal epigenetic process leading to parentalspecific expression of a gene, known to be implicated in the control of gene dosage in the neurogenic niches. The generation of induced pluripotent stem cells from NSCs by expression of defined transcription factors, provide key insights into fundamental principles of stem cell biology. Epigenetic modifications can also occur during reprogramming of NSCs to pluripotency and a better understanding of this process will help to elucidate the mechanisms required for stem cell maintenance. This review takes advantage of recent studies from the epigenetic field to report knowledge regarding the mechanisms of stemness maintenance of neural stem cells in the neurogenic niches.

Premature losses of leaf area in response to drought and insect herbivory through a leaf lifespan gradient

Implications of the differences in leaf life span are still subject to debate in the field of ecophysiology.Since leaf traits associated with these differences may be decisive for determining the distribution of tree species,this topic is particularly relevant in the context of climate change.This study analyzes the effects of the differences in leaf life span on premature losses of leaf area owing to insect herbivory and to abiotic stress.Loss of leaf area may be an important determinant of total leaf carbon assimilation.Seven Mediterranean tree species,distributed on four sites with different climates were studied.The species exhibited strong differences in leaf life span and in leaf traits,especially leaf mass per unit area.Premature leaf area losses were estimated in response to insect herbivory and summer drought over two years.The results revealed that,despite having older leaf cohorts with more damage,species with longer leaf duration had lower area lost to herbivores and less damage due to accelerated senescence during the summer drought.With respect to the predicted increase in water stress,deciduous species are at a disadvantage due to their high premature loss of leaf area and thus loss of photosynthetic capacity.

Spatial analysis and structure of a cross-timber stand in the TallGrass Prairie Preserve (Pawhuska, Oklahoma)

I analyzed the spatial distribution and structure of trees in a cross timber forest in the Tallgrass Prairie Preserve （Pawhuska, Oklahoma, USA）. I mapped and measured diameter of all stems, saplings （〉1.5 m tall） and dead trees in a 4-ha plot. The stand was dominated by Quercus stellata and Q. marilandica. In total, I mapped 7,636 trees, consisting of 6,785 Q. stellata, 846 Q. marilandica, 2 Celtis occidentalis, 1 Fraxinus pensilvanica and 2 Prunus americana. For saplings, I mapped 54 Q. stellata and 21 Q. marilandica. The size class distribution of the two dominant species did not differ. The dominant mortality class was “standing dead”, while I only found saplings less than 2 m tall. The spatial distribution of the species indicated segregation in the use of the environment, generating a clumped univariate distribution of stems of the same species within radii of 30 m, but repulsion outside 30 m. This segregation can be explained by the different ecological requirements of each species.

Larvicidal activity of Neem oil and three plant essential oils from Senegal against Chrysodeixis chalcites(Esper, 1789)

Objective: To evaluate the insecticide, larvicidal and repellent activity of the essential oils from Callistemon viminalis, Melaleuca leucadendron, and Hyptis suaveolens against Chrysodeixis chalcites and to compare it with neem oil(Azadirachta indica). Methods: The essential oils of the leaves of these aromatiques plants were extracted by steam distillation and contacts tests were carried out. Results: Essential oils in ethanol from Callistemon viminalis showed a higher biological activity than the neem with 100% larval mortality at the concentration of 2 μg/m L for 6 h, 100% and 90% in ethanol from Melaleuca leucadendron and Hyptis suaveolens, respectively at the concentration of 4 μg/m L for 24 h. By inhalation, the essential oils from Melaleuca leucadendron and of Hyptis suaveolens were more effective with mortality rates of larvae 100% and 50% respectively at 2 μg/L air applied after 24 h. Nevertheless, the neem has shown to be a repulsive plant and anti-nutritional plant. A significant difference in the percentages of consumption between leaves treated with neem oil and the control samples was observed(Newman-Keuls test) except for Melaleuca leucadendron. Conclusions: The results of the study highlight remarkable biocide, properties of tested extracts, which provides important opportunities for the development of biopesticides.

Development and Application of a Modified Genetic Algorithm for Estimating Parameters in GMA Models

In this work we introduce a modified version of the simple genetic algorithm (MGA) and will show the results of its application to two GMA power law models (a general theoretical branched pathway system and a mathematical model of the amplification and responsiveness of the JAK2/STAT5 pathway representing an actual, experimentally studied system). The two case studies serve to illustrate the utility and potentialities of the MGA method for concerning parameter estimation in complex models of biological significance. The analysis of the results obtained from the application of the MGA algorithm allows an evaluation of the potentialities and shortcomings of the proposed algorithm when compared with other parameter estimation algorithm such as the simple genetic algorithm (SGA) and the simulated annealing (SA). MGA shows better performance in both studied cases than SGA and SA, either in the presence or absence of noise. It is suggested that these advantages are due to the fact that the objective function definition in the MGA could include the experimental error as a weight factor, thus minimizing the distance between the data and the predicted value. Actually, MGA is slightly slower that the SGA and the SA, but this limitation is compensated by its greater efficiency in finding objective values closer to the global optimum. Finally, MGA can lead to an early local optimum, but this shortcoming may be prevented by providing a great population diversity through the insertion of different selection processes.

Diversity of Saxicolous Lichens along an Aridity Gradient in Central México

Lichens are symbiotic organisms that comprise a fungus and a photosynthetic partner wich are recognized as a good indicator of climate change.However,our understanding of how aridity affects the diversity of saxicolous lichens in drylands is still limited.To evaluate the relationship between saxicolous lichen diversity and aridity in a central México dryland,a geographical transect was established of 100 km to build an aridity gradient in the semiarid zone of the State of Querétaro,Mexico,comprising ten sampling sites with a 10 km separation.Species richness,abundance and diversity of soil lichen species were recorded using two sampling methods:the quadrat-intercept and the line-intercept method,to compare their performance in assessing soil lichen diversity in drylands.The number of species and Shannon diversity of saxicolous lichens were higher at intermediate values of the aridity index(AI=0.10-0.34).Quadrat intercept and point intercept methods gave quite similar results,which means that the selected method does not influence the results in a significant way.This study confirms the role of saxicolous lichens as climate change indicators and reveals the importance of the sampling method selection in the evaluation of different parameters of soil lichen diversity in drylands.

Diversity Dimensions of Freshwater Fish Species around the World

The quality and coverage of the available taxonomical and geographical information and the recognition that diversity is multi-faceted are two main factors that hinder to understand the spatial and temporal variations of biodiversity. In this study, we aim to quantify the global distribution of five diversity components used to assess freshwater fish diversity in river basins around the world. The multidimensional character of these diversity components was estimated and the so obtained diversity dimensions mapped. This was done taking into account those well-surveyed basins discriminated by considering collector’s curves, and additionally by controlling for the effect of survey effort on all considered diversity components. A total of 1,472,109 occurrence records were analysed, corresponding to 17,292 species of freshwater fishes. Five diversity components were considered: functional richness, species richness, taxonomic diversity, and two rarity measures. Well-surveyed river basins were discriminated using accumulation curves. The effects of survey biases and knowledge gaps were minimized by determining the relationship of each component with the completeness values calculated for each river basin. The geographical pattern derived from raw data is skewed by the unequal knowledge available, and all diversity components were positively correlated with completeness values. The first dimension described the association between species richness and functional diversity. The second dimension represented rarity and taxonomic diversity. The congruence between species richness and functional diversity suggests that ecosystem functions increase with the number of fish species present in river basins and that a decrease in species richness may involve a loss of functionality. The levels of rarity and taxonomic diversity of many species-poor basins found in arid and cold regions suggest that the distinctiveness of their freshwater fishes is primarily a consequence of how isolated these basins are.

Photochemical Efficiency during the Establishment and Consolidation Phases of in Vitro Pinus radiata Micrograft Made from Scions of Different Ontogenetic Age

The aim of the present study was to evaluate the applicability of maximal photochemical efficiency of photosystem II (Fv/Fm) as an early estimate of P. radiata micrografts viability coming from different position (basal vs. apical) in the ortets. We hypothesize that Fv/Fm variation is a good indicator of micrograft’s viability and phenological stage during micrograft development. The micrografts were established in QL medium supplemented whit 0.1 mg·L-1 IBA and 1 mg·L-1 BAP and cultured at 25°C ± 2°C and 80 μmol photons m-2s-1 of photosynthetic active radiation by 16 h per day. During the establishment and consolidation phase, we found significant differences in Fv/Fm with respect to time and buds positions provenience. During establishment, basal shoot tips have lower Fv/Fm than apical shoot tips, which agrees with the lowest viability (35%). However, during the consolidation phase, the trend changed and basal shoot tips presented higher Fv/Fm than apical shoot tips and showed an increase in ETR and NPQ, with respect to apical shoots and ortet. Although the measurement of fluorescence parameters implies the insertion of the fluorometer sonde in vitro, this implies aseptic considerations, but always conveies a contamination risk. We conclude that fluorescence (Fv/Fm, ETR, NPQ) can be indicators of the micrograft’s development according to the shoot tips position in the ortet and can be useful early-indicators of the scions’ physiological condition during micrograft transition from establishment to consolidation.

Comparative Study of Bioactive Components and Quality from Juices of Different Mandarins: Discriminant Multivariate Analysis of Their Primary and Secondary Metabolites

A comparative study of the primary and secondary metabolites of the juice of several mandarin cultivars with different pollination, seed production and parthenocarpic abilities was carried out, and the antioxidant capacity of the hydrophilic fraction was measured. Correlation by a Principal Component Analysis and a Cluster Analysis was used. By a multivariate analysis, the 15 citrus cultivars were clustered into four groups consistently with citrus types. The presented data are an important factor for choosing varieties with high potential as a nutraceutical source. These aspects are necessary as consumers demand prevention of health problems through nutrition and certain fruit quality traits, including fruit size, internal quality, good rind color and easy peeling.

Screening of Protease Inhibitory Activity in Aqueous Extracts of Marine Invertebrates from Cuban Coast

Protease inhibitors have been isolated from many variable sources;however, the need to identify and characterize new molecules has increased with the discovery of new therapeutic targets and the lack of specificity of already identified compounds with inhibitory activity. The goal of this work was to search for inhibitory activity against four proteolytic enzymes already recognized as therapeutic targets: human neutrophil elastase, dipeptidyl peptidase IV, subtilisin from Bacillus licheniformis and cathepsin K in selected marine invertebrates from the Caribbean Sea. A systematic screening was carried out with selected aqueous extracts belonging to 20 species from seven different phyla: Annelida, Bryozoa, Chordata, Cnidaria, Equinodermata, Mollusca and Porifera, all collected at the coast of Havana (Cuba). All extracts showing initial inhibitory activity were characterized in terms of IC50 values and specific inhibitory activity (SIA). Model enzymes were used in the case of human neutrophil elastase (porcine pancreatic elastase) and cathepsin K (papain) for the screening and all positive results were confirmed by testing toward the therapeutic targets. Ten extracts were identified showing inhibitory activity against human neutrophil elastase, for which the most promising values were obtained for Nerita peloronta. Only one extract, Bunodosoma granulifera, showed inhibitory activity against dipeptidyl peptidase IV with rather poor values of IC50 and SIA. Seven extracts showed inhibitory activity against B. licheniformis subtilisin with very good IC50 and SIA values for Lissodendorix isodyctialis, Cenchritis muricatus, and N. peloronta. Finally, eight extracts were positive for cathepsin K with almost similar parameters values among them. All these results confirmed the richness and potential of the marine invertebrate’s fauna and indicated new promising sources for the identification of natural compounds with potential application in therapeutics.

Floral biology and pollination mechanisms of four Mexico-endemic Fuchsia species with contrasting reproductive systems

Aims The evolution of the outstanding variation of reproductive systems in angiosperms has been considered an important driver of line-age diversification.Closely related hermaphroditic and dioecious species with biotic pollination provide the opportunity to study and compare traits related to pollinator attraction and their con-sequences on reproductive components.A higher predictability of pollination syndromes is expected in dioecious species,which are dependent on pollinators,than in self-compatible hermaphroditic taxa.Dioecious species may suffer pollen limitation depending on the quality of floral rewards and the kind and abundance of pollina-tors,whereas no pollen limitation is expected in hermaphroditic spe-cies with autonomous self-pollination.Additionally,in the absence of pollen limitation,more or better seeds are expected in dioecious species,according to the sexual specialization hypothesis.Methods In natural populations of the hermaphroditic Fuchsia fulgens and Fuchsia arborescens and dioecious Fuchsia parviflora and Fuchsia obconica,all endemic to Mexico,we first described flower phenol-ogy,flower production and longevity and nectar volume and concen-tration.Then,we evaluated the correspondence between floral visitors and pollination syndromes.In hermaphrodite plants,we determined the level of herkogamy and the potential for autonomous self-pollina-tion.Finally,we evaluated the effect of pollen limitation on fruit set and seed number and assessed seed germination for all species.Important Findings In contrast to our prediction,dioecious species did not show a higher correspondence between pollination syndromes and floral visitors than did hermaphrodites;however,male flowers exhib-ited a higher correspondence than female flowers.No pollen limitation was detected in dioecious species,for which visitation rate did not differ between male and female flowers.The her-maphroditic F.fulgens showed pollen limitation for seed number,despite the presence of autonomous selfing.Fruit set from auton-omous pollination was higher in F.arborescens,which showed a lower level of herkogamy compared with F.fulgens.Finally,dioecious species produced fewer but heavier seeds compared with hermaphrodite species.Although Fuchsia is classified as an outcrossing genus,both hermaphroditic species showed autono-mous self-pollination.The heavier but lower number of seeds per fruit in dioecious species may be related to the more efficient resource allocation expected from sexual specialization.This could play an important role in the evolution of dioecy;however,a comparative phylogenetic approach is required to confirm this hypothesis.

Ontogenetic transition in leaf traits: a new cost associated with the increase in leaf longevity

Aims Recent work has identified a worldwide‘economics’spectrum of correlated leaf traits that mainly reflects the compromises between maximizing leaf longevity and short-term productivity.However,during the early stages of tree growth different species tend to exhibit a common strategy,because competition for soil water and nutrients forces the maximization of short-term productivity owing to the need for rapid growth during the most vulnerable part of the tree’s life cycle.Accordingly,our aim here was to compare the variations that occur during ontogeny in the different leaf traits(morphology and leaf chemical composition)of several coexisting Mediterranean woody species differing in their leaf life spans and to test our hypothesis that tree species with a long leaf life span should exhibit larger shifts in leaf characteristics along ontogeny.Methods Six Mediterranean tree species differing in leaf life span,selected from three plots located in central-western Spain,were studied during three growth stages:seedlings,juveniles and mature trees.Leaf life span,leaf morphology(leaf area,dry weight,thickness and mass per unit area)and chemical composition(N and fibre con-centrations)were measured in all six species.The magnitude of the ontogenetic changes in the different traits was estimated and related to the mean leaf longevity of the different species.Important Findings Along ontogeny,strong changes were observed in all variables analysed.The early growth stages showed lower leaf thickness,leaf thickness and mass per unit area and N,cellulose and hemi-cellulose concentrations than mature trees,but a higher lignin content.However,these changes were especially marked in species with a longer leaf life span at maturity.Interspecific dif-ferences in leaf life span,leaf morphology and chemical com-position were stronger at the mature stage than at the seedling stage.We conclude that greater plasticity and more intense strat-egy shifts along ontogeny are necessarily associated with long leaf life span.Our results thus provide a new aspect that should be incorporated into the analysis of the costs and benefits associ-ated with the different strategies related to leaf persistence dis-played by the different species.Accordingly,the intensity of the alterations in leaf traits among different growth stages should be added to the suite of traits that change along the leaf economics spectrum.

Resource-sharing strategies in ecotypes of the invasive clonal plant Carpobrotus edulis: specialization for abundance or scarcity of resources

Aims Carpobrotus edulis(L.)N.E.Br.is known to invade many coastal ecosystems around the world,and it has been considered as one of the most severe threats to numerous terrestrial plant communi-ties.Therefore,the study of the relationships between life-history traits that may favour its invasiveness and the invasibility of the environments is necessary to improve our knowledge about inva-sion success.In this research,we specifically tested the effects of physiological integration in genotypes from contrasting habitats,where the importance of integration is expected to differ.Thus,the main objective of this work was to detect the presence of adaptive plasticity in the capacity for clonal integration in this aggressive invader.Methods In a greenhouse experiment,we compared the performance,in terms of growth and photochemical efficiency,of two C.edulis ecotypes.Connected and severed ramet pairs from coastal sand dunes and rocky coast habitats were grown in substrates of different quality and heterogeneity.Important Findings Our study clearly indicates that clonal integration improves growth and photosynthetic efficiency in the aggressive invader C.edulis.Two differ-ent aspects of clonal integration determine site-specific strategies in this species in order to optimize its successful propagation in a particular habitat.We demonstrated that the adaptation of C.edulis to local envi-ronments has led to a differential selection of two complex clonal traits associated with the capacity for clonal integration.In patchy sand dunes,C.edulis has evolved ecotypes with ramets highly plastic in patterns of biomass allocation,which allows ramets to specialize in the acquisi-tion of the resource that is locally most abundant,i.e.,a spatial division of labour among ramets.However,in the harsher rocky coast habitats,local adaptation produced highly integrated ecotypes,where resource sharing is not combined with a specialization of resource acquisition.

Sexual dimorphism in water and nitrogen use strategies in Honckenya peploides: timing matters

Aims Sexes of dimorphic species often differ in ecophysiological traits and display spatial segregation.These differences have been interpreted as an evolved response of the sexes to meet the specific resource demands associated with reproduction.Sexes may differ not only in the amount of resources allocated to reproduction but also in the tim-ing of allocation to reproduction.In this study,we hypothesize that as a consequence of their specific resource demands for reproduction,the sexes of the dune plant Honckenya peploides differ in terms of tempo-ral patterns of water use efficiency and nitrogen use and acquisition.Methods Water use efficiency,as inferred from leaf carbon isotope discrimi-nation(Δ^(13)C),nitrogen use,estimated by leaf nitrogen isotope com-position(δ^(15)N),and the foliar carbon and nitrogen contents were measured in males and females at three different points in time.Important Findings Females had greater water use efficiency than males,regardless of time.The ratio of N^(15) to N^(14) did not change with time in males,but significantly decreased in August for females.The total N content in the leaf tissues of females decreased as the season progressed,while in males a decrease was only found from April to June and then it remained constant from June to August.A similar pattern,but reversed,was followed by the foliar C/N ratio.Additionally,nega-tive relationships between leafΔ^(13)C and N content were found at all times for males and only at the end of the season for females.Thus,our hypothesis that sex-specific patterns of nitrogen and water use efficiency will depend on time was supported.Overall,our results highlight the importance of including time in studies of sex-ual dimorphism,and also the role that physiological specialization plays in meeting the specific demands associated with reproduction.

Stress-preventing effects of the anaesthetic agents 2-phenoxyethanol, MS-222, clove oil and metomidate in the Senegalese sole Solea senegalensis

Objective: To determine the effectiveness of the anaesthetic agents 2-phenoxyethanol, MS-222, clove oil and metomidate in attenuating acute handling stress in juvenile specimens of Solea senegalensis subjected to two routine stressful events specific to aquaculture and/or fish research. Methods: The stress-preventing effects of four anaesthetic agents (2-phenoxyethanol, 600 mg/L;metomidate, 5 mg/L;clove oil, 30 mg/L and MS-222, 75 mg/L) were evaluated in juvenile specimens of Senegalase sole (Solea senegalensis) subjected to two different types of acute (handling-related) stress: air exposure and net handling (chasing). To assess the stress-preventing effects of the four anaesthetic agents, diverse blood and plasma parameters (haematocrit, haemoglobin, glucose, lactate and cortisol levels) were determined as stress indicators. Fish were treated with the anaesthetic agents before being subjected to the different types of acute stress, and they were sacrificed 30 min, 2 and 24 h later. Control fish were processed in the same way without pretreatment with the anaesthetic agents. Results: The net handling stress was of sufficient intensity to cause a significant increase in the levels of most of the stress indicators considered. By contrast, air exposure stress only induced significant increases in cortisol and haemoglobin levels. Conclusions: The stress-preventing effects of the anaesthetic agents tested were ranked on the basis of their capacity to prevent increases in the haematocrit, haemoglobin, glucose, lactate and cortisol levels, as follows: metomidate (5 mg/L) > clove oil (30 mg/L) > MS-222 (75 mg/L)> 2-phenoxyethanol (600 mg/L).